Casper Ruud headed into the 2022 season with just one Grand Slam appearance that lasted as far as the fourth round anywhere and was determined to improve his record at the four most important events in tennis.

Hardly ideal. Just look at him now: Ruud is into the semifinals at the US Open and has a shot at moving up to No. 1 in the ATP rankings, following a run to the final at the French Open.

The 23-year-old from Norway, who is coached by his father, former professional player Christian, parlayed what he called "a better start than I ever had before in a match'' to a 6-1, 6-4, 7-6 (4) victory over 2021 Wimbledon runner-up Matteo Berrettini in the quarterfinals under a closed roof at Arthur Ashe Stadium on a rainy Monday.

He is the first Scandinavian man to reach multiple major semifinals in the same year since Sweden's Magnus Norman in 2000, and the first Norwegian player to make a US Open semifinal.

"During Paris, something clicked, and I feel like I, this year, have sort of figured out the better way how to play five sets and knowing that it's very different from playing best-of-three sets.

Sometimes realizing, or knowing, that you can sort of let one set go every once in a while to save some energy for the rest of the sets,'' the No. 5-seeded Ruud said. "So I think I matured and learned how to play five sets better than I did last year.''

"Everything sort of went [in] my favor,'' Ruud said. "I was hitting all the spots, all the shots that I needed to.'' Berrettini's take: "After 20 minutes I was [down] 5-0. I don't know how really. I don't know what happened.''

Sprinting through a sublime first set in which he produced just two unforced errors, it looked like Ruud was on track for a blowout victory when he was up 5-1 in the second set.

But Ruud mustered a comeback, breaking Berrettini in the ninth game, and then never trailed in the tiebreak.