Good friends and doubles partners, but there could only be one winner Tuesday on the singles court.

It was Karen Khachanov who kept his cool to down Andrey Rublev 7-6(8), 6-4 in the pair’s fourth-round clash at the Mutua Madrid Open. The 10th-seeded Khachanov took control of a closely fought encounter by rallying from 4/6 to claim the first-set tie-break and he carried that momentum to a one-hour, 42-minute victory on Manolo Santana Stadium.

“It’s always tricky to play against each other because on one side we know each other’s games perfectly because we’ve been training together for so many years,” said Khachanov. “At the same time we know what to expect, but also of course a bit nervous to play against each other. We are good friends, but on the court we are rivals.

“It was all a matter of keeping the serve, and if you have any chances on the return, go for it. That’s what I did.”

Khachanov saved the only break point he faced and won 80 per cent (35/44) of points behind first serves to take a 3-2 lead in his ATP Head2Head series with Rublev. The pair also met in Monte-Carlo three weeks ago, when Rublev prevailed en route to lifting his maiden Masters 1000 crown.

“Both of us served really well and we didn’t have any chance on return in the first set,” said Khachanov of the pair’s Madrid clash. “The tie-break was really crucial I would say, pretty similar to how it was in Monte-Carlo. He took the first set in a tie-break [there] and started to believe more in the second set.”

With his Madrid win, Khachanov moved to 19-0 in matches when he has won the first set in 2023. The 26-year-old, who has risen one spot to No. 11 in the Pepperstone ATP Live Rankings as a result of his Madrid run, will take on defending champion Carlos Alcaraz or 13th seed Alexander Zverev next at the clay-court ATP Masters 1000 as he attempts to reach his third tour-level semi-final of the year.

Despite his Madrid campaign coming to an end, the World No. 6 Rublev is still in the hunt for a trophy at the Caja Magica. He and Khachanov are set to take on Jamie Murray and Michael Venus in the quarter-finals of the doubles.

“At the end of the day, this match is over,” said Khachanov when asked about returning to court alongside Rublev. “We need to have some time maybe to absorb it. That’s how it was in Monte-Carlo. The day before we played doubles, we lost a very tight match, and then the next day he beat me. After one day, life goes on. He’s doing well this year, I’m doing well, I’m just happy.”