Nadal advances at US Open after hard-fought win over Khachanov

New York : Defending champion Rafael Nadal has advanced to the round of 16 of the US Open with a 5-7, 7-6, 7-6(7), 7-6(3) victory over Karen Khachanov.

The world No. 1 overcame pain in his right knee to dispatch the 27th-seeded Russian in a match that went on for nearly four and a half hours on Friday -- the longest contest so far at the 2018 tournament, reports Efe news.

After getting off to a slow start and losing the first set, the Spaniard came back to win the next three, though the final two went to tie-breakers.

"He is a great opponent, and it was a tough situation. There are things to work on for the next round," Nadal said after defeating Khachanov.

Nadal's next opponent will be Georgia's Nikoloz Basilashvili, who defeated Argentina's Guido Pella 6-3, 6-4, 1-6, 7-6 (7-4) earlier on Friday.