Novak Djokovic of Serbia reacts after defeating to Philipp Kohlschreiber of Germany at the 2014 US Open tennis tournament in New York, September 1, 2014. [Photo/Agencies]

NEW YORK -- Playing mostly mistake-free tennis, top-seeded Novak Djokovic reached the quarterfinals at the US Open for the eighth year in a row and at a 22nd consecutive Grand Slam tournament overall.

Djokovic, the 2011 champion at Flushing Meadows, made only 19 unforced errors, saved both break points he faced, and breezed past 22nd-seeded Philipp Kohlschreiber of Germany 6-1, 7-5, 6-4 Monday.

The last time Djokovic was eliminated before the quarterfinals at a major was a third-round loss to Kohlschreiber at the 2009 French Open. But Djokovic has now won their four head-to-head matchups since then.

Employing his court-covering defensive style to perfection, Djokovic repeatedly forced Kohlschreiber to hit an extra shot, and the German wound up with nearly twice as many unforced errors, 36.

Still, Kohlschreiber,who eliminated the last American man in the field, 13th-seeded John Isner, in the third round at Flushing Meadows for the third straight year _ had a chance to make Monday's match far more intriguing. Ahead 5-4 in the second set, with Djokovic serving, Kohlschreiber hit a forehand winner and then forced a rare backhand error at 30-all to earn a set point.

But Djokovic fended that off with what he later called a "really good" forehand passing shot winner to get to deuce, then held serve for 5-all and broke in the very next game to regain control.

"Managed to win that set, which was crucial," Djokovic said.

Next up for the Serb, who reached the USOpen final each of the past four years, will be a match against 2012 USOpen champion Andy Murray or ninth-seeded Jo-Wilfried Tsonga.