Top seed Novak Djokovic progressed into the second round of Wimbledon with a 6-3 7-5 6-4 victory over Florian Mayer.
Mayer put up a gutsy fight against the 2011 champion on Centre Court, however the world number one outlined his title credentials with a convincing display.
A break in the 11th game of the second set proved the key moment for the Serb.
Fourth seed David Ferrer beat Martin Alund 6-1 4-6 7-5 6-2 and eighth seed Juan Martin del Potro eased to a 6-2 7-5 6-1 success over Albert Ramos.
Meanwhile, Philipp Kohlschreiber raised eyebrows when he quit his first-round match against Ivan Dodig when trailing 2-1 in the fifth set.
The 16th-seeded German, who reached the quarter-finals a year ago, had taken the first two sets, only to allow Dodig to level.
Kohlschreiber had been upset at a number of line calls during the clash on Court 18 and he said: "I'm totally exhausted.
"In the last two or three days I was almost entirely in bed. I have had flu and felt like my body was pretty bad. I had no energy left.
"I have only been able to practice for 45 minutes over the last two days. I tried to hang in as long as I could but in the end I was tired and slow in the head and felt a pain in my leg.
"Maybe it was bad timing but it is hard to speak about because this is the best grand slam I played last year. I'm angry and sad but there is nothing I can do."
Djokovic, meanwhile, admitted there is still room for improvement in his game, despite recording a straight-sets victory.
He told BBC Sport: "It was my first match on a grass court this season and my first at Wimbledon, and I'm satisfied.
"It was tricky, because Florian Mayer is a very good opponent with a good variety of shots. His game is suited to grass. It took a lot of effort to come through.
"There are still a few things I would like to do better on. I could serve better. But my game is there. I'm still trying to find my rhythm."
Seventh seed Tomas Berdych eased past Martin Klizan 6-3 6-4 6-4, while ninth seed Richard Gasquet was a 6-7 (2-7) 6-4 7-5 6-4 victor over Marcel Granollers of Spain.
German 13th seed Tommy Haas ended Dmitry Tursunov's involvement with a 6-3 7-5 7-5 triumph, but Australian Bernard Tomic defeated American 21st seed Sam Querrey 7-6 (8-6) 7-6 (7-3) 3-6 2-6 6-3.
Gilles Simon, the 19th seed, also fell as grass-court specialist Feliciano Lopez notched up a 6-2 6-4 7-6 (13-11) victory over the Frenchman.
Milos Raonic and Grigor Dimitrov both enjoyed straight set successes as they progressed, while there were also wins for Kei Nishikori, Kevin Anderson,Jeremy Chardy, Andreas Seppi and Alexandr Dolgopolov.