Really frustrated that we can't watch this, but it's already outstanding that Dan has taken a set from IMO one of the 2 or 3 most talented players outside the top 10. We all know the Latvian can play tennis from the Gods or tennis from the local park, depending on what side of the bed he got out of in the morning (or more pertinently whether he even made it to bed the night before), but Ernests was very consistent, focussed and successful for the bulk of 2013, so we have to assume he hasn't lapsed.
Good luck Dan! If Gulbis should go a break down, he can blow a fuse very easily and give up/tank, so it's not impossible Dan could pull this off, even if unlikely on the balance of probabilities