On Bet365, the odds are @6.5 for the match to be between 24-26 (inclusive) games. I find this to be great value so thought I would share since I reckon there is a really high chance that if the game ends in two sets, it will hit. Another bet would be for match to go 3 sets if you want to make a bet that covers in case the first bet loses.
Good luck all if you decide to do it.