Andy Murray insisted he is playing well enough to beat Juan Martin Del Potro in the third round of the French Open after battling past Martin Klizan.

The world No1 needed three hours and 35 minutes to defeat the world No50 from Slovakia, eventually coming through 6-7 (3), 6-2, 6-2, 7-6 (3).

It was a very patchy performance from Murray, who started poorly and then got himself into trouble again at the start of the fourth set before mounting a comeback.

The victory set up a clash with former US Open champion Del Potro, who is still working his way back up the rankings after wrist problems that almost ended his career.

The Argentinian benefited from the emotional retirement of Nicolas Almagro during their second-round match when Del Potro himself was struggling with a groin injury.

But, assuming he is close to fully fit, Del Potro will present a serious test of Murray’s Roland Garros ambitions.

The Scot was determined to send a message of positivity, saying: “I definitely feel like I’m capable of winning that match.

“I’m playing way better than I was two weeks ago, and today’s match will have done me a lot of good, because physically I pulled up well and felt good, so I will gain a lot of confidence from that. And I also hit a lot of balls out there, more than the first round match.

“It seems like everyone thinks I didn’t play particularly well today, but there was some good stuff against a tough opponent. It’s not easy to play against someone like him. So hopefully I will keep improving in the next one.”

If Murray was positive off court, it was a different story on it, with the top seed maintaining a dialogue of vitriol towards himself and his support camp.

Coaches Ivan Lendl and Jamie Delgado, fitness coach Matt Little and physio Mark Bender are very used to being in the firing line, and it is something Murray has tried to improve. But he accepts the negativity is not good for team morale.

"I certainly didn’t want a fifth set."



Popcorn in hand, we take a look back at world No.1 Murray's 2R clash with Klizan. #RG17 pic.twitter.com/TykXK7oeHH — Roland-Garros (@rolandgarros) June 1, 2017



“I think a lot of time when I’m playing and especially when I’m frustrated or down, I don’t always project a lot of positivity on the court,” he said.

“Sometimes I think also for my team it’s difficult to know exactly how I’m feeling or what it is that I need when I’m on the court. So I think my job is really to try to be more positive while I’m out there.

“And I think that kind of helps everyone. I think they also feed off that a little bit, as well. But the last few months have obviously been tough, not been a lot of good stuff going on out there. When I’m getting frustrated, I think it’s not easy for them, either.”

Former British No1 Greg Rusedski, commentating on the match for Eurosport, believes Murray will need to improve to beat Del Potro.

Rusedski said: “That was patchy, a bit up and down and you just don’t see the confidence that he normally has going into a grand slam event. Yes Martin Klizan is dangerous but Andy just didn’t have that consistency.

“We’re just waiting for the great tennis from Andy Murray and he’ll need it in the next round against Juan Martin Del Potro. He needs more consistency, if he’s as patchy against Del Potro he’s not going to get through.”

Klizan has had some stand-out wins in the past but came into the match nursing a calf injury that almost forced him to miss the tournament.

There was no sign of that early on, though, as the 27-year-old blasted forehand winners past a passive Murray. The Scot struggled to find any depth or penetration on his shots and, although he broke Klizan when he served for the set, he played a very poor tie-break. Murray did not hit top form in the second set either, although he won it comfortably, but was playing better by the third.

However, just when it looked like he would finish the match going away, as he had in his opener against Andrey Kuznetsov, Murray dropped the first three games of the fourth set and got bogged down in a scrap once more. The fourth set alone lasted 78 minutes but, having broken Klizan when he served for a set for the second time in the match, Murray dominated the tie-break.

The Scot, meanwhile, threatened a sit-down protest over the positioning of spidercam, the moving camera above the court.

“I just said, If it’s there in my ball toss again, I’m going to sit down and wait for it to move, because I just don’t feel I should have to be asking for it every change of ends to not be there,” he said.

* From PA