Australian John Millman has suffered an upset in the second round of the New York Open, losing to Guillermo Garcia-Lopez in a tight three-setter.

The world No.102 Spaniard broke the fourth seed’s serve just once on his way to a gutsy 7-6 (7-4) 1-6 6-4 victory in two hours and 11 minutes.

It leaves Jordan Thompson as the only Australian left in the ATP 250 event after booking a quarter-final clash with big-serving American John Isner, who beat Bernard Tomic in straight sets.