'Rock star' quality separates Sharapova

Maria Sharapova did not just reach the third round of the US Open on Wednesday, she also showed that she is a rock star who never disappoints her fans, according to former world No 1 Mats Wilander.

"The saying 'the heart of a champion' was invented for her," Wilander, who is at the tournament as an analyst for Eurosport TV, said in a daily chat with Reuters.

"She does not have mental meltdowns. It's amazing.