British Tennis Forum - Celebrating 20 Years!

indiana · Tennis legend

Week 26 - The Championships, Wimbledon (grass) - men's qualifying

pauldepstein · Junior player

It makes no sense to me that Jubb is a big betting favourite against Tirante.
I did google about this but I still don't have a clue.

The facts are: Both are 24/25 so it's not like Jubb is super-young and likely to be improving rapidly.
There is no H2H record.
Tirante is much higher-ranked.
Tirante's peak ranking is much higher.

Is there some inside info that's putting the odds out of sync with the players' rankings?
Are there injury rumours or personal-upset rumours around Tirante?

Of course, the surface plays a role but ranking is a massively more important factor than the surface.

Paul Epstein

pauldepstein · Junior player

indiana wrote:
pauldepstein wrote:
indiana wrote:
OK, so the Court 2 double of Oliver T and Jan is 16.5
Of course, such a bet would be a terrible idea. If you take the view that both those bets are attractive, it's much more sensible to simply bet on both of them individually.
(This viewpoint can be justified mathematically by equations -- I used to do that for a living.)
Hmm, I'm not sure it is particularly justified mathematically.
If these are the individual odds against ( of course they judge the true odds really a bit more against, given the bookies' margin ) then the multiple is the approximate odds against of the double ( might be something in multiplying the bookies' margin too but I fail to see it makes the double a terrible option, - it is what it is, pretty unlikely but not tha I can see particularly worse value ).
Anyway, I had already covered both options - 2 wee singles and a double.

It's a modelling question. If we model the probabilities as being what the bookies say they are, then you are correct that the double is ok. But this isn't a good model.

As you suggest, the problem is the margin -- accumulator betting increases it which is bad for the customer (and therefore good for the bookie).

Let's assume the bookmaker gives you 2.875 on an event that has a 1/3 probability of occurring. (If you bet 8 and win, you will walk away with 23 instead of 24.)

The bookmaker's margin is 2/3 * 1 + 1/3 * -1.875 = 2/3 - 0.625 = 0.0417.

Now, if you take two separate bets at 2.875, the bookmaker's margin is still the same -- just over 4 percent.

But what happens if you consider the accumulator bet -- winning probability is 1/9. 2.825 ^ 2 = 7.981.

The bookmaker's margin is now 8/9 * 1 + 1/9 * - 6.981 = 11.3 percent.

As I said, I did this for a living for over 5 years so I probably know what I'm talking about.

indiana · Tennis legend

Ha, I'm too tired now but genuinely interested in having a proper read through and a wee bit more consideration of this another day.

I bet relatively small amounts but bet quite a lot and I am up on the year so far, percentage-wise not a lot ( about 4% ) but still up and it keeps me amused. So I would prefer to avoid "terrible idea" bets.

-- Edited by indiana on Sunday 22nd of June 2025 11:02:25 PM

Danny1312 · Intermediate Club Player

JonH comes home wrote:
Danny1312 wrote:
indiana wrote:
Lots of early British action tomorrow with leading the way on courts 1, 2, 3 and 4.

Court 2 with Oliver T's tough looking one, followed by Jan, may be worth bagging a seat if I can get myself there in good time.
No idea if Oliver is okay on grass? The French guy can be volatile though and I think lost to Hussey? Fery also should've beaten him, no idea on if Oliver will be as capable to push and frustrate him though... utterly looking forward to it all tomorrow though!
JoMo beat Atmane at Ilkley, two sets but quite close ones. Atmane had a meltdown.

So he lost to JoMo there and Giles in Birmingham and should've lost to Fery too... still fav but come on Oli!

Blue_Belle · County player

pauldepstein wrote:
It makes no sense to me that Jubb is a big betting favourite against Tirante.
I did google about this but I still don't have a clue.

The facts are: Both are 24/25 so it's not like Jubb is super-young and likely to be improving rapidly.
There is no H2H record.
Tirante is much higher-ranked.
Tirante's peak ranking is much higher.

Is there some inside info that's putting the odds out of sync with the players' rankings?
Are there injury rumours or personal-upset rumours around Tirante?

Of course, the surface plays a role but ranking is a massively more important factor than the surface.

Paul Epstein

But is it? Because Jubby has played well on grass previously and his opponent has not.

indiana · Tennis legend

It rather depends what the ranking difference is ( assuming reasonably genuine rankings ) and how much better / worse the two players are perceived to be on the particular surface.

I can't see that you you can have a particular rule of thumb but to my mind if not that big a rankings difference then the surface can become a bigger factor than the rankings.

Quite clearly there are other factors than rankings or the higher ranked would always be favourite, and I do think surface ( and grass particularly, sometimes more clay ) can certainly be one.

That's a fairly big rankings gap against Paul but I know nout about Tirante other than his ranking and that he's Argentinian ( and I wouldn't go betting nor assume odds would be varied vis a vis the surface just on nationality stereotypes ).

JonH comes home · Tennis legend

For all those attending qualies this week, really enjoy yourselves and send us some reports. Where i am they have two English channels on the TV, BBC 1 Northern Ireland and BbC2, haha. We didnt bring a pc or anything with us and my phone seems to say BBC I player is not viewable here, so Im reliant on the updates from the live scores and those on the ground!

But more important, have fun!

pauldepstein · Junior player

indiana wrote:
Ha, I'm too tired now but genuinely interested in having a proper read through and a wee bit more consideration of this another day.

I bet relatively small amounts but bet quite a lot and I am up on the year so far, percentage-wise not a lot ( about 4% ) but still up and it keeps me amused. So I would prefer to avoid "terrible idea" bets.

-- Edited by indiana on Sunday 22nd of June 2025 11:02:25 PM

Do you bet with bookies or betting exchanges or both?

Making 4% profit is extremely impressive.

Since bookmakers won't accept customers who are unprofitable for them, then assuming you are talking about bookies

rather than exchanges, this means that either bookies see your profits as being due to chance rather than sustainable, or

they haven't monitored your account properly. Obviously, the monitoring is automated and it may be somewhat crude.

Reading your post again, I see a possible clue in your qualifier "the year so far".

If you're up on "the year so far" but down on a lifetime-history basis, then bookies will assume that this is just a lucky year

for you, and will see you as a profitable customer. If you manage to recoup losses that you made on other years (if any),

they may close down your account.

The assumptions are automated and not subjective. Most monitoring systems will never bar anyone who has lost money

over the lifetime of their account.

"Terrible idea" is certainly hyperbole on my part. For example, if someone earns a normal middle class wage and bets £10 a month,

there are no significant economic losses no matter what happens. I suppose I was just using a hook to refer to the mathematical ideas.

Paul Epstein

Coup Droit · Tennis legend

I bow absolutely to Pauldepstein's superior knowledge

Although he can't tell us why paul is so favoured by the general public's betting flows - the wonders of betting, or trying to understand the general public, or both biggrin

The answer, though, I'm sure, is primarily the surface.

He is a clay player. He was playing last week on clay.

He's won a quali match twice on grass, but I think that's it. He never plays any other tournaments on grass - last year he played on clay the week before, played Wimbly qualis, and then went and played on clay the week after.

Paul on the other hand has a lof of grass under his belt.

And, although rankings matters, every year you see players at Wimbly qualis who just look rank awful on grass - and don't really care - they don't expect to win, they don't really care if they win, they've barely bought new grass tennis shoes - not worth the money. But they're getting £15.5k (and just possibly £26k if they get lucky) so worth turning out for.

Exactly like Indy, I bet a lot on tennis (as in a lot of bets) but in small (sometimes very small ) amounts

And come out each year in profit by about 5-10%

Which sounds great and would suggest ramping it up - but I know that if I ramped it up (a) I wouldn't enjoy it so much and (b) I probably wouldn't make the same profit, because you don't act the same when the amounts are bigger, it's common sense psychology

Now, I'm not betting on Paul's match but if I did so I probably would bet on Tirante - I think Paul will more likely win but the odds do seem a bit tight on him.

-- Edited by Coup Droit on Monday 23rd of June 2025 07:23:57 AM

JonH comes home · Tennis legend

An example might be in Eastbourne today where Jake plays Cobolli or Norrie plays GMP. Both the non Brits are seeded higher but Tennis Abstract which uses surface related data, rates both Brits as more likely to win - albeit narrowly - Jake at 57.5%.

This is purely surface related. Tennis abstract doesnt include home bias which I think betting sites do in terms of more bets going on home players by home punters. And as discussed before, TA uses as its base a surface adjusted ELO rating which takes into account quality of opponent. Weve discussed it before but theyve assessed it to, an average, perform in line with bookies, slightly better, and definitely better than official rankings in terms of predicting winners of matches.

www.tennisabstract.com/current/2025ATPEastbourne.html

JonH comes home · Tennis legend

TA doesnt post predictions for qualies so cant put those up Im afraid

indiana · Tennis legend

Re my 4% profit it is, as noted, just on this year so far, based on a lot of amost entirely maximum £10 bets, largely on tennis and football, with an online betting company. My profit I am sure is rather boosted by the super boost" odds offered quite regularly on a variety of sports.

Presumably there to entice folk in, I just automatically just go for the maximum £10 bet on these just about every time, often without knowledge, for they tend to be boosled to quite silly odds. And I just take overall profits from these with thanks.

Generally over other years I am probably very slightly ahead. This year I have taken more time to consider bets plus have more routinely "super boosted".

JonH comes home · Tennis legend

The weather looks good through Wednesday but Thursday looks, currently, to be wet all day, which may impact the end of qualies

Coup Droit · Tennis legend

indiana wrote:
Re my 4% profit it is, as noted, just on this year so far, based on a lot of amost entirely maximum £10 bets, largely on tennis and football, with an online betting company. My profit I am sure is rather boosted by the super boost" odds offered quite regularly on a variety of sports.

Presumably there to entice folk in, I just automatically just go for the maximum £10 bet on these just about every time, often without knowledge, for they tend to be boosled to quite silly odds. And I just take overall profits from these with thanks.

Generally over other years I am probably very slightly ahead. This year I have taken more time to consider bets plus have more routinely "super boosted".

Interesting smile

A few years ago, I tried for six months to do no 'bets from the heart'

I rather like having a little punt on some outsider French girl, at 9 to 1, say, even though she should be 20 to 1, really. It's a sort of, look, Manon, SOMEONE in the world supports you biggrin

When I cut those all out, for six months, I actually posted 19% positive returns. Which I was really pleased with. (Although it was still on small or very small amounts - I occasionally go for a £10 bet but those are pretty rare - most are £1, or under smile )

BUT I really didn't enjoy it so much - it was too much like 'work', too serious smile , so it's back to the old ways