Murray claims players who swear in English fall foul of authorities

Scot admits he must mind his language but believes foreigners get away with saying similar things

Andy Murray admits that he should not swear so much on court but believes that as an English speaker he is punished more than many other players. The world No 4 was given an official warning for a verbal obscenity during his opening victory over David Nalbandian in the Rome Masters at Foro Italico on Tuesday but says his opponent got away with much more because he was speaking in Spanish.

Television commentators have often had to apologise for Murray's language and the 25-year-old Scot said: "I swear on court regularly. I try not to, but sometimes you forget where you are and what's going on. It's a mistake and something I try not to do, but I also understand a lot of the stuff [Nalbandian] was saying, from my time in Spain."

Murray, who meets Richard Gasquet in today's third round, added: "Because what I say is in English, we're always the ones to get the warnings. What came out of my mouth was nowhere near the translation of the things [Nalbandian] said. But it's not right to do it and I deserved a warning."

Roger Federer, who said he rarely uttered inappropriate words on court in Swiss-German these days, said Murray was probably right about English-speakers being more likely to be warned. but added: "You shouldn't maybe do it, but who cares? Sometimes it's to yourself and who cares? It happens."

Federer was talking after winning his opening match against Argentina's Carlos Berlocq 6-3, 6-4. The Swiss admitted that he had decided to play in the tournament only after a practice session yesterday morning following his exertions last week, when he won the Madrid Masters in his first tournament of the European clay-court season: "I just wanted to see how I felt and make sure that I didn't have anything major because we're ahead of a long summer. If this was the last tournament of the season it would be no problem, but as this is the beginning of many tournaments in a row, potentially a lot of five-setters in a row, I need to make sure I make good decisions."

Rafael Nadal looked in good shape in his opening match, beating Germany's Florian Mayer 6-1, 7-5 in just 81 minutes.

In the women's tournament Serena Williams took her unbeaten run on clay to 15 matches, beating Nadia Petrova 4-6, 6-2, 6-3, while her sister Venus overcame Ekaterina Makarova 7-6, 6-1.

Agnieszka Radwanska lost 6-4, 4-6, 6-1 to the Czech Republic's Petra Cetkovska, who became only the second player to beat the world No 3 this year. All six of Radwanska's previous defeats in 2012 were at the hands of Victoria Azarenka.