Ruthless Federer eases to opening victory at ATP World Tour Finals November 6, 2012 -- Updated 1653 GMT (0053 HKT) Roger Federer needed just 68 minutes to demolish Serbia's Janko Tipsarevic at the ATP World Tour Finals. Roger Federer bidding for seventh title in ATP World Tour Finals Federer beats Janko Tipsarevic 6-3 6-1 in round-robin opener Federer lost No.1 ranking to Novak Djokovic this week Juan Martin del Potro and David Ferrer playing other Group B opener (CNN) -- Roger Federer was detained on court for a little over an hour Tuesday as he brushed aside Serbia's Janko Tipsarevic 6-3 6-1 in their opening round-robin match at the ATP World Tour Finals in London. Federer skipped last week's Paris Masters to rest ahead of his title defense at the O2 Arena and it looked to have paid off as he produced a commanding performance against the eighth seed. Tipsarevic also sat out last week's tournament with a virus and was always on the back foot after the Swiss maestro broke early for a 3-0 first set lead. Federer comfortably held his own service to take the opener in 30 minutes and the pattern continued in the second set. He broke to lead 2-1 and then swept through the next four games for his 40th victory in the season-ending finals, beating the previous record of 39 by Ivan Lendl. The 31-year-old won his 17th grand slam title at Wimbledon earlier this year, but his other visit to London saw him beaten by Andy Murray in the Olympics singles final. It's my third trip to London this year. The other two were pretty good and I hope something similar is going to happen this week," Federer said after his victory. Federer lost in the final of his home town tournament in Basel to Argentina's Juan Martin del Potro and his decision not to play in the French capital meant he lost his No.1 ranking to Novak Djokovic. Del Potro will play newly crowned Paris Masters champion David Ferrer in the other Group B tie later Tuesday. Djokovic and home hope Andy Murray began their Group A campaigns Monday with victories over Jo-Wilfried Tsonga and Tomas Berdych respectively. The top two in each group qualify for the semifinal knockout stage.