Roger Federer
Roger Federer of Switzerland hits a return to Jeremy Chardy of France during their match at the Rome Masters.

Frenchman Jeremy Chardy stunned world number four Roger Federer in the second round of the Rome Masters 1-6, 6-3, 7-6 (8-6) on Wednesday.

Federer, playing his first match after the birth of his second set of twins, swept the opening set in just 24 minutes, breaking his opponent's service twice. The Swiss committed just nine unforced errors compared to Chardy's 12 and ripped eight winners to take the lead.

The Frenchman started the second set confidently and broke Federer's serve in the third game. Federer failed to strike winners and get the break back, as Chardy reduced unforced errors in the second to force the decider.

Chardy put Federer under a lot of pressure in the final set and broke the maestro's serve in the fifth game and went on to hold his to build a 4-2 lead. The match seemed to be over when the Frenchman once again got a break point in the seventh game, but Federer held on and managed to take the set into the tiebreaker.

Chardy took an early 4-2 lead, but lost three points out of four on serve, leaving Federer with a 6-5 lead in the tiebreaker. The 47th-ranked player turned the tide one final time in the match, however, to complete a famous win over the 17-time Grand Slam Champion.

"The conditions were the same for all the players today," said Federer after the match. "Sure, it makes it difficult to have a proper game plan, or execute the way you want. Clearly, you're not going to take as many risks, you're just trying to put shots in play, rather than really go for it. I wasn't really able to stretch the lead when I had it. Unfortunately, it happened this way today.

Meanwhile, in an another second round match, defending champion Rafael Nadal was made to work hard by France's Gilles Simon 7-6 (1), 6-7 (4), 6-2 at the Foro Italico. Nadal, bidding for his eighth Rome Masters title, played two tie breakers before wearing down Simon in the decider.

The Spaniard looked to seal the first set comfortably, while serving at 5-4 and 6-5, but the Frenchman took the set into the tiebreaker, with Nadal keeping his composure and winning the tiebreaker 7-1.

Nadal was given a stern test by Simon in the second set, as he surrendered his early break advantage and once again was forced into the tiebreaker. Simon held his nerves in the second tiebreaker to win it 7-4 to force the final set.

The decider proved to be an easy ride for the top-seeded Nadal, who broke Simon's serve in the fifth game to wrap up the match in three hours and 19 minutes. The world number one will face Mikhail Youzhny in the pre-quarterfinals.

"The conditions were difficult, it was very cold and the ball didn't bounce a lot," said Nadal. "It was a tough moment in the second set, but this was the first match on clay where I had to suffer, mentally and physically. I was not playing bad and I am happy to have dealt with that kind of anxiety.

"I look forward to playing the third set because these are the matches that give me more satisfaction, the ones that test you very deeply. I did it and I am very happy," he said.

Watch the highlights of Roger Federer v Jeremy Chardy match HERE or HERE.

Watch the highlights of Rafael Nadal v Gilles Simon match HERE.