WIMBLEDON, England — John Isner didn’t mind waiting. In this, his 41st Grand Slam event, what was another four hours and 14 minutes?

That was how long Isner had to wait for eighth-seeded Kevin Anderson to knock top-seeded Roger Federer out of Wimbledon in a marathon five-set match. Next up on No. 1 Court was Isner, who had the highlight of his career nearly three hours later: a 6-7(5), 7-6(7), 6-4, 6-3 victory over 13th-seeded Milos Raonic to reach his first Grand Slam semifinal.

Isner described his feeling after the win as “pure elation.”

“With how I’m feeling physically and mentally, I’m in a very good spot; I think I can keep doing damage here,” he said. “This is amazing. It’s by far the best Grand Slam I’ve ever played in my career, and I’ve been playing for 11 years. I’m super happy. To do it here at Wimbledon makes it even a little bit more special.”

After starting his year with a 2-6 record, Isner, 33, has been playing the best tennis of his career. He won his first career Masters title at the Miami Open in early April and rode the momentum here, reaching the quarterfinals of a Grand Slam for the first time in seven years.