After dropping the opening set at love, American Sam Querrey charged back to stun Novak Djokovic, while Andy Murray and red-hot Juan Martin del Potro avoided second-round upsets at the $3.15 million BNP Paribas Masters, the final ATP World Tour Masters 1000 tournament of the year.

Querrey managed to win only 10 points in a 20-minute first set before fighting back for an unlikely 0-6, 7-6 (7-5), 6-4 victory at Bercy's Palais Omnisports. The second-seeded Djokovic actually led 6-0, 2-0 before Querrey mounted his comeback, which was completed in just over two hours.

The 23rd-ranked Querrey fired 18 aces and was broken only once in the upset of the 2009 Paris Masters champion Djokovic, who was this year's Australian Open winner and French and U.S. Open runner-up.

"I thought I served amazing, especially the big points. I felt like I made a first serve there every time," Querrey said. "I could see he was struggling a little bit, missing some shots he probably wouldn't normally miss."

This marks Djokovic's earliest loss since March 2010.

"During the second set I already felt that physically I'm down, and I struggled every game," Djokovic said. "It's unfortunate, but on the brighter side, I have a little bit more time to rest because I had really difficult period in the last couple of weeks. Some things happened and a lot of things on my mind."

Djokovic learned on Monday that he will finish as the year-end No. 1 for a second straight year. He will supplant current No. 1 Roger Federer atop the rankings next week. Federer pulled out of this Paris event Sunday night after losing to del Potro in the finale at the Swiss Indoors Basel.

Meanwhile, the third-seeded Murray handled oft-injured Frenchman Paul-Henri Mathieu 7-5, 6-3 and a seventh-seeded del Potro won his 11th straight match with a 6-2, 6-2 pasting of qualifier and fellow South American Alejandro Falla of Colombia. Murray fired 12 aces past the wild card Mathieu.

Murray was this year's Wimbledon champion and Olympic gold medalist. Del Potro is seeking his third title in three weeks, having titled in Vienna two weeks ago and Basel last week.

Up next for Murray will be 6-foot-8 Pole Jerzy Janowicz, while del Potro will face French left-hander Michael Llodra.

Fourth-seeded David Ferrer avoided an upset by leveling fellow Spaniard Marcel Granollers 6-1, 6-3. The six-time 2012 ATP champion Ferrer is fresh off his title in Valencia in his native Spain last week.

Ferrer's third-round opponent will be 16th-seeded Swiss Stan Wawrinka.

The wild card Llodra moved on by upsetting 10th-seeded American John Isner 6-4, 7-6 (7-5). Isner fell despite striking 15 aces, but he also had his serve broken once while failing to break the veteran southpaw Llodra.

Meanwhile, eighth-seeded Serb Janko Tipsarevic topped Dutch qualifier Igor Sijsling 6-4, 7-6 (7-0); ninth-seeded Argentine Juan Monaco got past Bulgarian qualifier Grigor Dimitrov 7-6 (7-4), 6-2; 11th-seeded Nicolas Almagro outlasted fellow Spaniard Albert Ramos 7-6 (7-1), 6-7 (4-7), 6-3; and 14th-seeded Milos Raonic of Canada beat Jeremy Chardy of France 6-7 (4-7), 7-6 (7-4), 6-3.

Also on Day 3, South African Kevin Anderson upended 12th-seeded Frenchman Richard Gasquet 7-6 (7-5), 4-6, 6-1 and France's Gilles Simon bested Romanian lucky-loser Victor Hanescu 7-5, 6-3. Hanescu replaced last year's Paris Masters champion Federer in the draw.

The newest Paris Masters champ will pocket $620,000.