Roger Federer has defeated a hobbling John Isner 6-1 6-4 for his 101st career title at the Miami Open.
Isner struggled to continue late in the second set on Monday (NZ time), hampered by pain in his left foot.
Federer, who won his fourth Miami title, broke Isner three times in a blazing opening set.
"It was a dream start, relaxing my nerves," the Swiss player said in a courtside interview.
But the American fought back in the second, levelling the set 3-3 and 4-4 before the pain made it difficult to continue.
Federer took the final two games for the victory.
"What a week its been for me," he said.
"I'm just so happy right now. It's unbelievable. I played here in 1999 for the first time, and here I am in 2019. It means a lot to me."
Only American Jimmy Connors, with 109, has more career singles titles.
Even before the injury slowed Isner, Federer was the master, tempering Isner's big serves and winning 32 of 35 points on his own serve.
Federer elected to receive to open the match and the strategy paid off as he broke Isner.
The American held on the third game, but Federer took the next four.
Isner played much better in the second set, but in the end, the pain became too much for him to mount an effective defence.