The world number one needed three hours and 35 minutes yesterday to defeat the world number 50 from Slovakia, eventually coming through 6-7 (3/7) 6-2 6-2 7-6 (7/3).
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.”
“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 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.
“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.”
World number three Stan Wawrinka came out on top in his slugfest with Ukraine’s Alexandr Dolgopolov win 6-4 7-6(5) 7-5 and move into the third round. Kei Nishikori survived an injury scare and Jeremy Chardy’s late revival to advance into the third round. Richard Gasquet beat Victor Estrella 6-0, 6-1, 6-4, while home hope Gael Monfils beat Thiago Moura Monteiro (Bra) 6-1 6-4 6-1.
An angry Nick Kyrgios was knocked out of the French Open on Thursday, going down 5-7 6-4 6-1 6-2 to South African Kevin Anderson in the second round.
The temperamental Australian destroyed two rackets, including one that he smashed six times onto a cooler, and was handed a penalty point at the end of the second set.
The 18th seed has never made it past the third round at the Paris grand slam. Anderson next faces Britain’s Kyle Edmund.
In the women’s, Simona Halep strolled into the third round of the French Open with a no-nonsense 6-4 6-3 victory against unheralded German Tatjana Maria on Thursday.
The Romanian third seed, who reached the Roland Garros final in 2014, was no match for world number 102 Maria, who bowed out on the first match point on Court Suzanne Lenglen.
Halep never seemed bothered by the ankle problem that could have ruled her out of the tournament.
She next faces Russian 26th seed Daria Kasatkina.
Second seed Karolina Pliskova survived a see-saw encounter against unheralded Russian Ekaterina Alexandrova 6-2 4-6 6-3 to reach the third round for the first time. Ninth seed Agnieszka Radwanska dug deep to see off Belgian qualifier Alison Van Uytvanck 6-7(3) 6-2 6-3.