Andy Murray believes he has to improve his serve despite comfortably beating John Isner in straight sets to book a French Open quarter-final against Richard Gasquet.
World number two Murray won 7-6 (11-9) 6-4 6-3 against the big-serving American, but insisted he still has work to do on his game if he is to compete for the title.
Murray was never in danger against Isner and controlled the match, but the Scot says his serve is an area he wants to improve in the next round.
"I think it's obviously important to serve well," Murray said at his post-match press conference.
"But I think I can do a little bit there if I'm serving that well on the break points, I need to find a way of serving like that all of the time, not just when you're behind, serving well is a positive thing, for sure.
"I got myself in some difficult situations in the last couple of service games, I think I missed eight first serves in a row in that last game, so I can do a bit better there."
Second seed Murray looked forward to a last-eight meeting with home favourite Gasquet, who he has beaten twice at Roland Garros.
"Well, [I played him] once in the first round on [Court Suzanne] Lenglen," Murray said. "It was a tough first-round match. I managed to sneak through.
"And then we played on [Court Philippe] Chatrier, as well. It was actually raining quite a bit that day when we played. It was very heavy, cold conditions.
"I think I lost the first set and I won in four. I didn't get off to the best start that day. I don't remember loads about the matches. I played a lot since then, it was quite a long time ago."
Despite needing five sets in his first two matches at the tournament, Murray added he feels fit enough to go further into the competition.
"I feel fine now. The matches weren't physically draining," Murray said. "Mentally they can be challenging. There are a lot of points that feel very important against Ivo [Karlovic] and against John, but physically I feel fine.
"Between now and the end of the tournament, they are completely different matches - a lot more rhythm, longer points, you know, more physical matches.
"So I'll need to change the way I'm playing a little bit and make some adjustments for those matches."