Andy Murray believes Laura Robson can get right to the top of the tennis world if she keeps working hard to improve her movement.
The 18-year-old came of age at the US Open on Wednesday night with victory over Kim Clijsters in the second round. It was by far the biggest win of Robson's career and took her through to the third round of a grand slam for the first time, where she will play ninth seed and former French Open champion Li Na.
Murray is a good person to judge Robson's game given the pair's experience of playing mixed doubles together, and he said: "When we were playing I didn't say too much. We just tried to play and not over think it so much. The one thing (I saw), when I first played with her at the Hopman Cup, she has the potential to move actually fairly well."
He added: "She moved very well on the court (yesterday). But you need to want to chase balls down and believe that you can get to balls, and I think at the Olympics, after the first match or so, she was getting to a lot of balls. She was moving much better than she had in the past.
"She hits the ball great when she's in a good position. I think if she keeps improving on her movement, she's going to be a very, very good player.
"She's very good already, but she'll get to the top much quicker."
Murray looked back to his own breakthrough grand slam win, over Andy Roddick at Wimbledon in 2006 when he was 19, and he thinks Wednesday's win it can be a landmark moment for Robson.
The 25-year-old said: "I played Roddick at Wimbledon. That would probably have been my first big win at a major. He's obviously played very well at Wimbledon in the past.
"It does give you confidence. She's had some close matches against top players before in the slams. She's played (Maria) Sharapova a couple of times, at Wimbledon and at the Olympics.
"She's good. She's very competitive when she plays against them. It's going to take a bit of time to get the consistency and whatnot, but she's a very good player."