Every top sportsman or woman enjoys proving people wrong, but few seem to revel in it as much as Andy Murray.

As the Scot begins week two of the French Open here today, he will do so in good heart, believing he has turned the corner thanks, in no small part, to those who said he would be long gone by this stage.

From arriving in Paris with doubts about his form, confidence, health and even fitness, Murray broke free of the shackles in his straight-sets win over Juan Martin Del Potro in round three.

Today, he will play the young Russian, Karen Khachanov for a place in the quarter-finals. Should he win, it’s an achievement he will enjoy all the more for the fact that few expected him to make it.

“To be playing the way that I am now, I'm very pleased and happy for myself that I'm doing it,” said Murray, whose form on the clay before Paris this year had been very poor, with three early exits in four events.

“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 few sets [against Del Potro], so I'm happy I've managed to turn it around.

Murray admits he doubted himself coming into the event, unsure just why he was not able to reproduce the kind of form that helped him become world No 1 at the end of 2016.

A bout of shingles, flu and an elbow injury didn’t help his confidence but with that seemingly restored, and with Rafael Nadal and Novak Djokovic in the other half of the draw, he will believe that he can at least reach the semi-finals, where he is seeded to face third seed Stan Wawrinka.

“The further that you go, the better you start to feel, the more confidence you get and you are in the second week of a slam, so anything is possible,” Murray said.

“Why not set the bar as high as possible? It's better to say 'OK, I want to try and win the tournament' and fall short and lose in the final than 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 few sets today, then there is no reason why I can't win a few more matches.”

At 30, having achieved a career-goal in becoming No 1 last year, motivation may have been a factor in his early-season difficulties.

Though he made the semi-finals in Barcelona, early exits in Monte Carlo, Madrid and Rome left Murray looking under-done as he arrived here but his inner belief has always been strong.

“Things can change very quickly, you don't become a bad tennis player overnight,” he said.

“It can only take one or two good practices, providing you're trying to do the right things in practice. Even when you're not playing well, if you're training hard and trying to do things right, things can turn around very quickly.

“I felt like I could turn it around. It wasn't going to be easy but I feel like I've done a good job of that. I'm playing way better than I was a week, 10 days ago.”

Nadal continues to look like a man on a mission, the nine-time champion demolishing fellow Spaniard Roberto Bautista-Agut 6-1, 6-1, 6-2.

And the defending champion Novak Djokovic also showed improved form as he beat Spaniard Albert Ramos-Vinolas 7-6, 6-1, 6-3, finishing off just in time before the light faded last night.