LONDON -- Wimbledon's defending champion is through to the second round.
Novak Djokovic beat Philipp Kohlschreiber of Germany 6-4, 6-4, 6-4 Monday in the first round, playing the first match of the tournament on Centre Court.
Djokovic, who won the Australian Open this year and then lost in the French Open final, is the man to beat at the All England Club again this year. The top-seeded Serb won his second Wimbledon title last year, and came into this year's tournament with a 41-3 record.
"It's great to be back," Djokovic said. "This is the cradle of our sport, Centre Court. It doesn't get any better than Wimbledon. I am privileged and honored to open this year's Wimbledon Centre Court as defending champion. It really is a special feeling."
Kohlschreiber, the highest-ranked men's player outside the seedings at No. 33, had figured to pose a stiff test for Djokovic, who came to Wimbledon after a painful loss to Stan Wawrinka in the French Open final and without having played a warm-up tournament on grass.
But the Serb was rarely troubled, seizing command with his all-court game, serving 12 aces and breaking five times.
"I had a very tough opponent who can be very tricky on all surfaces. Especially on the grass, he had nothing to lose," Djokovic said. "I just managed to stay composed."
Djokovic displayed frustration in the post-match news conference when he was asked for a second straight day about comments by his coach, Boris Becker, that they have ways of communicating with each other during matches.
Coaching during a match is against the rules, but Djokovic said that is not what is going on.
"Do you want to say I'm cheating? My team?" he said. "I'm really trying to figure out what's behind this.
"There are certain ways of communication -- which is encouragement, which is support, which is understanding the moment when to clap or say something that can lift my energy up -- that can kind of motivate me to play a certain point," Djokovic added. "But it's all within the rules."
Seeking to become the first to defend his title since Roger Federer in 2007, Djokovic improved to 7-1 for his career against Kohlschreiber and hasn't lost in the first round of any Grand Slam event since the 2006 Australian Open.
Wawrinka also played on Centre Court, and the fourth-seeded Swiss looked sharp on the grass as he beat Joao Sousa of Portugal 6-2, 7-5, 7-5 (3). Wawrinka could face Djokovic in the semifinals.
Meanwhile, Lleyton Hewitt has played his last match at Wimbledon as the 2002 champion lost to Jarkko Nieminen 3-6, 6-3, 4-6, 6-0, 11-9 in exactly 4 hours.
Hewitt, a former top-ranked player from Australia, won the title the year before Federer started his run of five straight championships and has said he will retire from the sport after next year's Australian Open.
After a warm embrace with Nieminen at the net, Hewitt went back onto the court without his racket to acknowledge the loud ovation and wave to the fans.
Fifth-seeded Kei Nishikori of Japan was extended to five sets by Simone Bolelli on Court 1 before prevailing 6-3, 6-7 (4), 6-2, 3-6, 6-3. Other men's winners Monday included No. 9 Marin Cilic, No. 16 David Goffin, No. 17 John Isner and No. 26 Nick Kyrgios.
The 17th-seeded Isner -- best known for winning the longest match in tennis history at the All England Club in 2010 -- hit 38 aces in a 7-6 (5), 6-4, 6-4 victory over 91st-ranked Go Soeda of Japan in the first round.
Isner collected more than half of his points, 58 of 96, via unreturned serves.
The match took only 1 hour, 45 minutes -- a sprint for Isner, who famously edged Nicolas Mahut 70-68 in the fifth set of a first-rounder five years ago that lasted more than 11 hours spread over three days.
Isner never has been past the third round at Wimbledon in six previous trips and is now 6-6 at the grass-court Grand Slam tournament.
The Associated Press contributed to this report.