FLUSHING MEADOWS, N.Y. -- Top seed Novak Djokovic beat Argentina's Diego Schwartzman in three sets Monday night in their first-round match at the U.S. Open.
Djokovic started his quest for an eighth Grand Slam title with a 6-1, 6-2, 6-4 win in the final match of the night at Arthur Ashe Stadium.
The Wimbledon champion Djokovic has a run of four straight finals at the Open, including a championship in 2011 against Rafael Nadal. Djokovic lost last year to Nadal, but the Spaniard isn't defending his title this year due to a right wrist injury.
Playing his first career tour-level main draw match on hard courts, the 22- year-old Schwartzman was no match for the world's No. 1 player. The Serbian breezed through the first two sets in 56 minutes. Schwartzman won the first game of the third set and then had a chance to break, but a smiling Djokovic roared back and evened the set with an ace.
There were a couple of hiccups from Djokovic, as Schwartzman broke to tie it at 3-3, but he couldn't follow it up. Djokovic broke back and then held at love before closing it out.
"It's never easy to start a U.S. Open smoothly," said Djokovic, who had 27 unforced errors, three more than Schwartzman.
Up next for Djokovic will be Frenchman Paul-Henri Mathieu, who topped Gilles Muller of Luxembourg in a five-set marathon.
"I'm sure we'll both be fresh and motivated to play," Djokovic said. "He's a very solid player from the baseline, but I'll focus on myself and hope to do as well as I did tonight."
Former champion Andy Murray was tested in his first-round match Monday, while third seed Stan Wawrinka and No. 5 seed Milos Raonic won their openers in straight sets.
Murray, the eighth seed and former world No. 2 star, battled cramps before holding off wily Dutchman Robin Haase 6-3, 7-6 (8-6), 1-6, 7-5 in 3 hours, 8 minutes.
"I don't know what it was. I was cramping after 1 hour and 45 minutes," Murray said. "I didn't know what to do in the third set. I started to get it in my laterals and forearms when I was serving. I didn't know whether to conserve energy or try to finish it.
"I tried to hang around and tried to play without using my legs much. I managed to get through. These slams are physically challenging, but I need to work out why it happened. It shouldn't have happened, regardless of the temperature."
Murray overcame a 1-4 deficit in the fourth set to get off the court before a fifth.
The two-time Grand Slam champion was the U.S. Open winner two years ago and runner-up in Flushing in 2008. His second-round opponent will be German Matthias Bachinger.
Wawrinka, this year's Australian Open champion, topped Czech Jiri Vesely, 6-2, 7-6 (8-6), 7-6 (7-3). Wawrinka, who is from Switzerland, reached his first U.S. Open semifinal last year before losing to Djokovic.
The Canadian Raonic eased past Japan's Taro Daniel, 6-3, 6-2, 7-6 (7-1). Raonic, who has reached the fourth round here the last two years, is trying to build on a semifinal appearance at Wimbledon when he lost to Roger Federer.
Ninth-seeded former Australian Open runner-up Jo-Wilfried Tsonga of France snuck past gritty Argentine Juan Monaco 6-3, 4-6, 7-6 (7-2), 6-1.
In other opening-day action involving seeds, No. 16 Tommy Robredo of Spain defeated Frenchman Edouard Roger-Vasselin, 6-4, 6-3, 6-4; promising Aussie Nick Kyrgios upended No. 21 Russian and two-time U.S. Open semifinalist Mikhail Youzhny 7-5, 7-6 (7-4), 2-6, 7-6 (7-1); No. 22 German Philipp Kohlschreiber handled Argentine Facundo Bagnis 6-2, 7-6 (7-3), 6-3; No. 23 Argentine Leonardo Mayer was leading Albert Montanes 6-2, 3-0 when the Spaniard retired; Benoit Paire took out No. 24 fellow Frenchman Julien Benneteau 7-6 (7-4), 5-7, 6-4, 4-6, 6-4; 30th seed Jeremy Chardy of France toppled Colombian Alejandro Falla, 6-7 (5-7), 6-2, 7-5, 6-4; and No. 31 Spaniard Fernando Verdasco outlasted Slovenian Blaz Rola 6-3, 3-6, 7-5, 1-6, 6-4.
Several other men moved on, including Italian players Andreas Seppi and Simone Bolelli.
Federer, the second seed and five-time U.S. Open champion, plays his first- round match Tuesday night against Australian Marinko Matosevic. Federer hasn't won the U.S. Open since 2008, the last of his five consecutive championships at the event.