World No. 1 Novak Djokovic needed six match points to tough out a 6-2, 6-4 win over Tennys Sandgren on Tuesday in the third round of the Western & Southern Open in New York.

The reigning Australian Open champ breezed through the final game by winning four straight points, closing it out with a cross-court forehand winner to clinch it in 88 minutes.

But American Sandgren made the Serb work for the victory as he survived five match points in the previous game.

Djokovic advances to the quarter-finals where he will play German Jan-Lennard Struff who defeated seventh seed David Goffin 6-4, 3-6, 6-4.

Djokovic had pulled out of doubles on Sunday with pain in his neck, but did not appear to be bothered by the injury against Sandgren.

The no-spectator tournament was moved from Cincinnati to New York where the same quarantine bubble will house the US Open starting on August 31.