Andy Murray described Juan Martin del Potro as "one of the best players in the world", but fully expects to beat him after progressing to the French Open third round at the expense of Martin Klizan.
The Briton prevailed 6-7 (3-7) 6-2 6-2 7-6 (7-3) against Klizan on Thursday and will face Del Potro next, with the Argentine going through after opponent Nicolas Almagro's injury-enforced withdrawal.
Murray has the better of the pair's head-to-head record, with his six wins from nine matches including a memorable Rio 2016 Olympics final success.
He anticipates a testing encounter with Del Potro, but responded emphatically when asked if he was in good enough form to triumph.
"Absolutely," he said. "Yes, it's a tough match, not an easy third round.
"He's, in my opinion, one of the best players in the world when he's fit and healthy. This year he's had a lot of tough draws.
"If you look at the matches that he's lost, I think he's played Novak [Djokovic] a few times. I think he lost to [Milos] Raonic in Delray Beach, Novak in Rome. [In] Miami I think he lost to Roger [Federer].
"So because of the ranking that he has, he's kind of in that bracket where he's met a lot of the top guys early on.
"But I definitely feel like I'm capable of winning that match. I'm playing way better than I was two weeks ago and [this] 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.
"I hit a lot of balls out there, more than the first-round match. It seems like everyone thinks I didn't play particularly well, but there was some good stuff against a tough opponent. It's not easy to play against someone like him."
Murray's on-court demeanour, which very often appears negative, is something he is criticised for and the 2016 Roland Garros runner-up conceded he needed to work on it.
"Getting frustrated on the court is something that I have always battled with and always fought, probably since I was 20, 21 years old, and it's more venting," he explained.
"Sometimes when I don't say anything, I come in and I get asked: 'Oh, you seemed very flat on the court.' You know, that's just how I am. I feel like I have improved it from where I was in the middle of my career. Yes, it's something I constantly try to get better at.
"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.
"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 that helps my whole team. I think they also feed off that a little bit, as well.
"But I think 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. "