Andy Murray delighted with his Paris progress but must now face one of the rising stars of the ATP Tour

The World No 1 has said he was always confident of turning around his poor form and will now face the talented Karen Khachanov for a place in the quarter-finals

Murray is through to the fourth round of the French Open (Getty)

Andy Murray is only halfway towards emulating his achievement of reaching last year’s French Open final, but the world No 1’s confidence is growing with each victory.

“I felt like I could turn it around,” Murray said here as he reflected on the poor form he had been in when he arrived at Roland Garros. “It wasn’t going to be easy, but I feel like I’ve done a good job. I’m playing way better than I was a week, 10 days ago.”

Having disposed of one 6ft 6in giant in the third round on Saturday when he beat Juan Martin del Potro in straight sets, Murray faces another on Monday in the imposing figure of Karen Khachanov, who is one of the best of a new generation of rising talent. The 21-year-old Russian, a big server with equally impressive ground strokes, is through to the fourth round on his French Open debut after beating John Isner 7-6, 6-3, 6-7, 7-6.

Murray had arrived here with just one win to show from his previous four matches and was on antibiotics after going down with another bug during a season in which he has been regularly beset by injury and illness.

“To be playing the way that I am now, I'm very pleased and happy for myself,” Murray said. “A lot of people wouldn’t have thought that I would maybe get to this stage or be playing the way that I did in the last two sets [against Del Potro], so I’m happy I’ve managed to turn it around.

“The further that you go, the better you start to feel and the more confidence you get. You are in the second week of a Slam, so anything is possible. Why not set the bar as high as possible? It’s better to say ‘OK, I want to try and win the tournament’ and to fall short and lose in the final than to say ‘I’m delighted getting to the second week’ and then lose in the fourth round.

“I want to try and go as far as possible, but there are no guarantees. If I play like I did in the last two sets [against Del Potro], then there is no reason why I can’t win a few more matches.”

Murray said he had not been playing well enough going into Roland Garros to think he could win the tournament but insisted: “Things can change very quickly. You don’t become a bad tennis player overnight. It can take only one or two good practices, providing you’re trying to do the right things.

“Even when you’re not playing well, if you’re training hard and trying to do things right, things can turn around very quickly. It can also turn around the other way as well if you stop doing things properly in practice, aren’t concentrating properly and aren’t having the correct game plan or game style going.

“I felt like I’ve been doing the right things in practice. In the matches maybe I was just not as switched on as I needed to be - and that can make a huge difference.

“In the matches here I think I’ve been more switched on. I didn’t play perfect tennis in the first three rounds, but [playing over the best of five sets] gives you a lot better chance of turning your form around and also winning matches just by playing smart.

“When I’m not playing well I can still win matches against top players. I did it last year a bunch. You need to remember that as well, providing you are willing to work hard and try to get through it.”

Murray is happy with the progress he has made in Paris (Getty)

He added: “Physically I feel pretty good. I haven’t seen any of the stats but I do feel like I’ve been dictating a lot more points these last couple of matches, doing less running than I did in the first two matches here last year, when I felt like I was defending the whole time.”

Khachanov, who has only just turned 21, is the youngest man to reach the fourth round at Roland Garros since Marin Cilic in 2009. The world No 53 climbed 99 places in the rankings last year and is set to break into the top 40 for the first time at the end of this tournament. He has won four of his last six matches against opponents ranked in the top 30.

Born in Moscow, Khachanov has been coached by Galo Blanco at the Spaniard’s academy in Barcelona for three years now. Blanco has worked with a number of top players in the past, including Milos Raonic and Feliciano Lopez.

Khachanov is one of the rising stars of the sport (Getty)

Although this is only the Russian’s third appearance in a Grand Slam tournament, Murray is well aware of the threat he poses.

“I practised with him before he got on to the tour when he was ranked about No 350 and he was really good,” Murray said. “He’s a big strong guy who generates a lot of power and also has a big serve.”

Isner sees Murray as the favourite but added: “Karen is playing with a lot of confidence. If he hits the ball as big as he did [against me] I think he can keep it close. He's certainly got to believe that he can win the match.”