Doubles partners turned singles foes at the Caja Magica as Karen Khachanov and Andrey Rublev put their friendship aside to produce a tightly-contested fourth round on Tuesday.

The pair, who are contesting the doubles quarter-finals together on Wednesday against Jamie Murray and Michael Venus, entered their singles clash with a 2-2 head-to-head against one another.

Their most recent meeting was a Rublev victory over Khachanov in the Monte Carlo fourth round.

This time in Madrid, it was Khachanov’s turn to come out on top as he defeated the Monte Carlo champion 7-6(8), 6-4 to reach a quarter-final of a Masters 1000 on clay for the very first time.

“I would say it’s always tricky to play against each other, because from one side we know each other’s game perfectly, because we’ve been training (together) so many years, we know what to expect, but also we’re a little bit nervous to play against each other, we’re good friends, but on the court, we’re rivals,” said Khachanov, who will take on top seed Carlos Alcaraz or No.13 seed Alexander Zverev in the next round.

Will they be okay to join forces in doubles tomorrow?

“I hope so, I hope he will play with me tomorrow, I need to see, I will ask him,” said Khachanov with a smile.

“But at the end of the day, this match is over, we need to have some time, maybe to absorb it for him. It was the same 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 it’s okay, life goes on. He’s doing well this year, I’m doing well, so we’re just happy. It’s unfortunate that we met in the fourth round.”

Very little separated Khachanov and Rublev in the match, with the duo putting up similar numbers. It was Khachanov though who played the important points better, holding serve throughout and claiming the sole break of the contest.

Neither player faced a break point in the opening set, which fittingly went to a tiebreak. A couple of loose backhands saw Khachanov get in trouble as he faced two set points, trailing 4-6.

He saved both though, which swung the momentum his way and it was Rublev’s turn to save two set points, one with a smooth volley winner that closed out a 20-shot rally.

The No.5 seed could not fend off a third as Khachanov broke down the Rublev backhand to take the opening set in just under and hour.

A poorly-executed drive volley from Rublev earned Khachanov an early break in the second set, which left his opponent enraged, smashing his racquet in frustration.

Some great defence from Khachanov saw the No.10 seed carve out two match points; and all he needed was one, a big serve punching his ticket to the quarter-finals after one hour and 41 minutes of play.

“Viva Espana,” wrote Khachanov on the camera lens to celebrate the win. The 26-year-old had picked up just one victory in Madrid, in five previous appearances, and explained why he has managed to do better at the Caja Magica this year.

“In Madrid it’s always a little bit of a different feeling, the altitude and the balls are flying much more. I think the years before, I was trying to play the same as I was playing the other years, but I think this year I changed a little bit the tactics and the strategy and I think it’s paying off. Hopefully I can continue that way,” said Khachanov.

A former world No.8, Khachanov has been playing some great tennis these past nine months, reaching the semi-finals at the US Open, Australian Open and Miami.