KAREN Khachanov has reached his first Grand Slam semi-final after upsetting new tournament favourite Nick Kyrgios in five hard-fought sets. The Russian 27th seed won 7-5 4-6 7-5 6-7 6-4 to book a place in the semi-finals where he takes on Norwegian fifth seed Casper Ruud.

After defeating world number one Daniil Medvedev – and dethroning the Russian from his top spot – Kyrgios was expected to knock off the top seed’s lower ranked compatriot, but it was not to be with Khachanov exacting revenge on behalf of his countryman to defeat the Australian 23rd seed in three hours and 39 minutes.

The Russian came within two points of victory in the fourth set, but could not close it out, as Kyrgios forced a fifth set thanks to winning a crucial tiebreaker. In a back-and-forth contest, the Russian produced a crucial break in the deciding set to win in tough conditions. Most of the Arthur Ashe crowd were behind the Australian, but the Russian held his nerve to fight it out and win in five sets to reach the final four for the first time in a major.

“I did it! I did it!,” Khachanov said post-match. “I’m really proud of myself, I was focussed from the beginning to the end. “It was a crazy match but I came ready to fight and to play five sets.”

It was much more straightforward for the highest remaining seeded player in the top half of the draw, as Norwegian Ruud came through with the goods against 13th seed Italian Matteo Berrettini. Ruud won in straight sets, 6-1 6-4 7-6 in two hours and 36 minutes to book his place in the semi-finals.

A Roland Garros finalist this year, Ruud found the going tough in the final two sets, but managed to put his opponent away. He did lead 6-1 5-1 at one stage before Berrettini forced his way back into the match.

It was a case of too little, too late though, as the fifth seed weathered 13 aces and 35 winners off Berrettini’s racquet to hit 20 winners, but only 23 unforced errors, breaking five times to two and 43 per cent of his receiving points in the victory.

“That was a better start than I think I ever had before in a match,” Ruud said post-match. “Everything was going my way, I was hitting all the spots I needed to plus Matteo maybe didn’t serve as well as he usually does. I was able to take care of the chances that I got.

“I got a little bit nervous towards the end of the second set, because things were almost going too well. It’s good, but sometimes you can get over-excited and start to think you can walk on water… So I had to calm down a little bit, and luckily was able to serve out the second set, and the third set was very tough.”

If Ruud makes the final and third seed Carlos Alcaraz does not, then the Norwegian will be crowned world number one on Monday.

US OPEN MEN’S SINGLES RESULTS: QUARTER FINALS

[5] Casper Ruud (NOR) defeated [13] Matteo Berrettini (ITA) 6-1 6-4 7-6
[27] Karen Khachanov (RUS) defeated [23] Nick Kyrgios (AUS) 7-5 4-6 7-5 6-7 6-4