On the ITF circuit, it shows whether the player has serve and ace or a DF, is there any site that will tell me at WTA level?
This is a Slam so they do their own thing, and it's not under the WTA auspices, or on their app. The individual match detail has the stats, and is here: http://www.usopen.org/en_US/scores/stats/12159ms.html#
Betting sites like bet365 often have the DF/Ace indications.