Wimbledon: Roger Federer confident over fitness after suffering back scare against Xavier Malisse ROGER Federer insists he will be fit enough to continue his fight for a seventh Wimbledon title despite suffering a back injury en route to victory over Xavier Malisse. Federer took a medical time-out after feeling a twinge in his back following the eighth game of the first set. He left the court and returned eight minutes later before dropping his serve to trail 5-6. Malisse failed to take his chance, though, and allowed Federer back into it. He raced through the tiebreak and the second set too. "I thought it was extremely difficult for Xavier," said Federer. I did apologise to him after the match just for the first set. I know how hard it is playing somebody that is injured. The third seed moved gingerly afterwards, but he still managed to record a 7-6 (7/1) 6-1 4-6 6-3 win that ensured his passage to a 33rd consecutive grand slam quarter-final. The 30-year-old Swiss thinks a combination of cold weather and his five-set win over Julien Benneteau, could have caused his injury, but he is confident the problem will have cleared up by the time he faces Mikhail Youzhny tomorrow. "I'm not too worried about it," Federer said. "Two good nights" sleep and I'm pretty convinced I'll be 100 per cent on Wednesday. Otherwise I wouldn't have been able to pull off the win the way I did today. I just felt it go at the start of the first set so I decided to have medical treatment. I've had bad backs over the years. They go as quick as they come. As well as his injury, Federer had to battle through the elements yesterday. At one point, play was suspended for 40 minutes, and high winds, cold temperatures and persistent drizzle made life difficult for both players on Centre Court. Tournament organisers came in for criticism for not closing the roof despite the fact that a bad forecast had been predicted, but Federer was glad they did not do so. "I was happy they kept it open because it's an outdoor tournament," Federer said. We don't want to play indoors all the time. It's not that big of a deal coming on and off. The conditions were tough. There was drizzle the whole time. We could have come off at any time. At times you're stressing out because you want to stretch the lead; sometimes you hope it rains so you can come off, so it also plays some tricks on you mentally. I think the situation helped my back. But maybe it would have happened anyway because I had a five-setter. Federer had to adapt his game after suffering the injury, opting for softer drop shots than powerful hits. Malisse showed flashes of brilliance throughout the match and the 31-year-old earned high praise from Federer. "He's a great player," the Swiss said. It's nice playing against him and I know it's hard to play against an injured opponent. Only Jimmy Connors, with 41, can better Federer's 37 grand slam quarter-finals in the professional era, but nobody has won more grand slam matches since tennis turned professional. Federer's victory over Malisse extended his grand slam win-loss record to 241-36.