Eight-time champion Roger Federer survived a first-set scare to see off South African debutant Lloyd Harris and reach the Wimbledon second round.
Federer, 37, moved through the gears to win 3-6 6-1 6-2 6-2 on Centre Court.
The Swiss, aiming for a record-extending ninth men’s title, will face Britain’s Jay Clarke next.
Third seed Rafael Nadal faced fewer problems against Japanese qualifier Yuichi Sugita, winning 6-3 6-1 6-3 to set up a meeting with Nick Kyrgios.
Harris, 22, had never even won a match on grass going into his meeting with arguably the greatest player of all time.
But the world number 86 rocked Federer with blistering serves consistently around 130mph and backed that up with some heaving groundstrokes in a first set which left Centre Court murmuring in disbelief.
After breaking Federer’s serve for a 4-2 lead, Harris confidently sealed the opener in 29 minutes as he threatened to create one of the most seismic shocks ever seen at Wimbledon.
Federer, who had dropped a set in the first round at Wimbledon for the first time since 2010, seemed to lack the assurance which has rarely gone missing in his illustrious career.
“I struggled early on. I felt a bit frozen, my legs weren’t going,” he told BBC Sport.
“I felt it was heavy out there, the ball wasn’t going when I was hitting it and he was hitting it big.”