Roger Federer has opened his 18th consecutive Wimbledon challenge with a 7-6 (7-5) 7-6 (7-3) 6-3 win over Argentina's Guido Pella.
The Swiss third seed, bidding for an eighth Wimbledon title at the age of 34, struggled to shake off a gutsy opponent before his class prevailed.
More importantly, he showed no sign of the back injury that forced him to miss the French Open, ending his run of 65 consecutive appearances at grand slam tournaments.
"I worked so hard to be here," Federer said.
"My hope was to be here fully fit. No one knows, not even myself. But we'll see."
Federer next plays world No. 772 Marcus Willis of Britain.
Under the watchful gaze of new coach and tennis royalty John McEnroe, Canadian sixth seed Milos Raonic got off to a solid start with a 7-6 (7-4) 6-2 6-4 win over Spain's Pablo Carreno Busta.
Novak Djokovic opened his bid for a third straight Wimbledon title and a fifth successive Grand Slam with a straight-sets win over Britain's James Ward.
French Open champion Garbine Muguruza said she had to play ugly to negotiate Wimbledon's perilous grass courts and a dangerous opponent.
But for an appreciative Centre Court crowd, the powerful tennis the elegant Spaniard produced in downing Camila Giorgi 6-2 5-7 6-4 looked very easy on the eye.
"Sometimes you don't win very beautiful, but you just got to be there, you know, and fight for the match," the 22-year-old said.
Muguruza, is no slouch on grass, having reached the final here last year but the aggressive Giorgi made her work hard to transfer her Paris clay punch to Wimbledon's lawns.
Former world number one Ana Ivanovic suffered a surprise first round exit, the 23rd seed was beaten by Russia's Ekaterina Alexandrova.
American eighth seed Venus Williams, the oldest player in the women's singles draw, beat teenager Donna Vekic 7-6(3) 6-4.
The New Zealand number one Marina Erakovic American Irina Falconi in three sets in her first round match.