Roger Federer urged himself not to miss when facing match points against Gael Monfils before winning at the US Open on Thursday.
The 17-time grand slam champion claimed a 4-6 3-6 6-4 7-5 6-2 win over 20th seed Monfils in their quarter-final at Flushing Meadows.
Federer saved two match points in the fourth set, but was largely untroubled thereafter as he set up a clash against Croatia's Marin Cilic.
The second seed said he simply wanted to make Monfils earn his victory when the Frenchman stood on the brink of victory.
"I still thought the finish line was far for Gael. I knew I could play better tennis," Federer said in an on-court interview.
"I got off to a good start, so I was actually feeling all right, but then when I was down two match points, that's when I wasn't feeling so great anymore.
"I thought, 'this is it. This is the last point, man. Just go down fighting, don't miss an easy shot and let him have it. It's fine.'
"But I served well and stayed in the match and somehow turned it around. I felt great in the fifth. I was really starting to play better and better as the match went on, and that's a great feeling."
Only a man he has never lost to stands between Federer and a 26th grand slam final.
Federer has a 5-0 win-loss record against Cilic, but remembers how hard he was made to work in a 7-6 (7-5) 6-7 (3-7) 6-4 victory in Toronto last month.
"I'm looking forward to playing Marin," he said.
"He's a great guy. We had a tough, tough match in Toronto. I think I needed nine match points to close him out and beat him at midnight, 6-4 in the third, so we know what to expect."