Novak Djokovic overcomes ailing American qualifier in US Open second round

Svajda, playing in only his seventh major main draw match, put up a good fight before an apparent leg injury limited his movement.

“Wasn’t happy about my tennis the first part of the match but also credit to Zach for playing some really high quality tennis,” said Djokovic, who next plays the winner of a match between Briton Cam Norrie and Argentina’s Francisco Comesana.

Svajda saved two break points in the first game, an early sign that he would not hand the four-time champion the win, and he survived a 27-shot rally in the tiebreak before sending a superb backhand shot out of Djokovic’s reach on set point.

But the Serbian seventh seed upped his level across the board from there, making just four unforced errors in the second set compared to 14 in the first, and he got the break in the sixth game as Svajda whacked the ball into the net.

There were more signs of trouble for the American as he met with the physio to have his left thigh massaged briefly before the third set and again after the third and fifth games, while his on-court speed diminished.

Djokovic got the critical break from the baseline in the seventh game of the third set with a well-placed forehand winner down the line and ran away with the contest from there.

He converted on his fourth break point in the second game of the fourth set and broke again for a 5-1 lead before wrapping up the win.