Wawrinka's progress is a menace to Murray

He has some way to go before he will overtake his country's No 1 player, but Stanislas Wawrinka is making decent progress up the world rankings. Andy Murray's opponent in today's second round of the Rome Masters climbed this week to No 24, his highest ever placing.

Playing second fiddle to Roger Federer in your homeland might unnerve some lesser mortals, but it has helped Wawrinka to reach the game's higher ranks almost unnoticed. In January the 23-year-old Swiss reached the final in Doha, where he was beaten in three sets by Murray, in March he won four matches in Indian Wells before losing to Novak Djokovic in the quarter-finals, and in Barcelona last week he made the semi-finals, with David Nalbandian among his victims.

"He's a strong guy, hits the ball hard on both wings and serves well," Murray said. "He's had good results on clay, but he's played well on most surfaces other than grass."

Murray, who also beat Wawrinka on his way to the Marseilles title in February, considers the Swiss one of his best friends on tour (they had talked about playing doubles together this week), which is more than can be said for his previous opponent. Murray's first-round victory late on Monday was an acrimonious affair in which the Scot fumed over comments he said Juan Martin del Potro had made during the second set about his mother, Judy, who was watching in the stand. Del Potro, who had previously angered Murray by failing to apologise for hitting a ball straight at him, retired after the recurrence of a back injury when trailing 5-7, 6-4, 1-0.

Although he did not reveal what Del Potro had said, Murray said he had told the Argentinian to "watch his mouth". He added: "My mother is one of the nicest ladies you're ever going to meet. He can say whatever he wants about me, but when you start talking about someone's family I think it's natural not to take it too well."

Having been warned for swearing, which he denied, Murray was unhappy that Fergus Murphy, the umpire, took no action against Del Potro. "I said: 'You warned me for not even swearing at the start of the match, but this guy is talking about my family and you're not going to do anything about that?' He said: 'Wait until after the match.' I think it merited a warning."

Murray was well on top by the time Del Potro retired and admitted the row had fired him up. "I wanted to win so much more after that," he said.

Today's winner will face either Rafael Nadal or Juan Carlos Ferrero, who beat Nicolas Kiefer 6-7, 6-3, 6-4 yesterday. Federer gained a 6-3, 6-3 victory over Guillermo Canas, who beat him in successive Masters Series tournaments last year, while Andy Roddick began his European campaign with a 6-1, 6-4 win over his fellow American, Mardy Fish.