As alluded to, Karlovic a bit fatigued after his Bogota win - Matt's luck as Karlovic retires after losing first set 2-6. Well done Matt in winning that set.
Matt plays another big server in the form of No.2 seed Kevin Anderson. Matt must be seeing the ball well after playing and beating both Gooch and Karlovic in consecutive matches, but Anderson will be fresh after having a bye in the first match. Hopefully Matt will be more used to the court conditions.