Top seed Novak Djokovic overcame a spirited challenge from Radek Stepanek to reach the third round at Wimbledon.
The Serb, beaten by Andy Murray in last year's final, had to dig deep before winning 6-4 6-3 6-7 (5-7) 7-6 (7-5) against the 35-year-old Czech.
"We practised together before Wimbledon so know each other's games well, but I shouldn't have complicated my life in that way," Djokovic told BBC Sport.
Queen's champion Grigor Dimitrov beat Australian qualifier Luke Saville.
The 11th seed from Bulgaria looked impressive in sweeping past the Australian qualifier, ranked 236 in the world, 6-3 6-2 6-4.
But seventh seed David Ferrer, who like Dimitrov was a potential quarter-final opponent for Andy Murray, and 12th seed Ernests Gulbis are both out.
Spaniard Ferrer was beaten 6-7 (5-7) 6-0 3-6 6-3 6-2 by Russian Andrey Kuznetsov, the world number 118.
Latvian Gulbis, the French Open semi-finalist, lost 6-4 6-3 7-6 (7-5) to Sergiy Stakhovsky, the world number 90 from Ukraine who knocked Roger Federer out of last year's tournament in the first round.
Stakhovsky will next face Frenchman Jeremy Chardy, who eventually overcame Australian Marinko Matosevic 6-7(5-7) 7-6 (7-9) 7-6 (11-9) 4-6 7-5.
Djokovic, whose last-32 opponent will be Frenchman Gilles Simon, knew he had been in a battle against Stepanek, who beat Andy Murray at Queen's.
"I was two sets up and had break point chances and I should have closed it out in the third-set tie-break," he said.
"But credit to him for fighting. He performs really well on the big stage, loves to engage the crowd and is a great entertainer.
"I came to Wimbledon without much match practice and didn't have much time on court in my first match, so I was focused because I was aware of his ability and quality.
"He doesn't give up and read my passing shot well. It was a difficult one but I am glad I managed to hang in there mentally to win."
Dimitrov, who is dating Maria Sharapova, has seen his game improve dramatically over the past 12 months and he can now look forward to a third-round match against 21st seed Alexandr Dolgopolov of Ukraine, who beat Germany's Benjamin Becker 6-7 (4-7) 7-6 (7-0) 6-3 6-4.
"I am confident at the moment but I knew Luke was a tricky opponent and I had to be composed the whole match," Dimitrov, 23, told BBC Sport.
"It was my first time to play on Centre Court so I was happy coming on because you don't get a chance to play on a court like that every day."
The 2010 finalist Tomas Berdych also advanced after overcoming Australian Bernard Tomic 4-6 7-6 (7-5) 7-6 (7-3) 6-1 despite being troubled by a wrist injury.
"It's something which is bothering me and if you have something like this, it's not the best feeling and the best help going into the match, even if it's not super painful," he said.
"It's something just giving you the sense that you cannot hit the backhand how you are used to."
The sixth seed's next opponent will be Croat 26th seed Marin Cilic, a 3-6 6-1 6-4 6-4 winner over Austrian Andreas Haider-Maurer.
France's Jo-Wilfried Tsonga, the 14th seed, twice fought back from a set down to force a deciding set against Sam Querrey of the United States only for their match to be suspended due to bad light at 4-6 7-6 (7-2) 6-7 (4-7) 6-3 9-9.
The match will resume on Thursday, meaning whoever wins will have to play for five successive days, with their third-round tie to be played on Friday.