Novak Djokovic enjoyed the briefest of Wimbledon openings before booking his spot in the second round when opponent Martin Klizan retired through injury after the first set of their match on Tuesday.
Djokovic, a three times Wimbledon champion, had taken the first set 6-3 before Klizan called the trainer on court to treat a leg injury.
The 47th-ranked Slovakian emerged for the second set, but was moving gingerly and was immediately broken by Djokovic, who then held to consolidate his lead before Klizan limped towards the umpire to pull out.
Second seed Djokovic, who is chasing a 13th grand slam title, came into Wimbledon after enduring a difficult year in which he relinquished his number one ranking as well as his grip on all four majors.
He will play Czech Adam Pavlasek in the next round.