Laura Robson has credited a run free of injury and tactical advice from her new coach for her stunning run to the fourth round of the US Open.
The 18-year-old defeated ninth seed Li Na on Friday to follow on from her breakthrough win against Kim Clijsters and in the fourth round will play yet another grand slam winner in defending champion Sam Stosur.
Robson began working with Croatian coach Zeljko Krajan, who previously masterminded the rise of Dinara Safina to world number one, after winning mixed doubles silver with Andy Murray at the Olympics last month.
Although it is too early in the relationship to credit Krajan with too much input, Robson has clearly benefited from the Croatian's tactical know-how.
She said: "I think the level has always been there. It's just in the last few weeks I have gained a bit of confidence and the work that I have done with him has been very specific in terms of tactical stuff.
"So just in the last few matches I think it's noticeable that, instead of just trying to hit a winner off a tough shot like I have done in the past, I'm trying to make a percentage shot back. That makes all the difference really.
"I have always thought that I can play with the top girls. Whenever I've practised with Caroline (Wozniacki) or Maria (Sharapova), I've always felt that the level was there.
"It was just taking that onto the match court and keeping the level up for the whole match."