Rory McIlroy reeled off five birdies on the back nine to take a one-stroke lead over Hunter Mahan after Thursday's opening round of the Shanghai Masters. England's Paul Casey and Ian Poulter and three-time major winner Padraig Harrington of Ireland were three shots behind McIlroy at 5-under 67. Anthony Kim of the US and Li Chao of China were another stroke back at 4-under 68. There are 10 major winners in the field, including three from this year: McIlroy, Masters winner Charl Schwartzel of South Africa, who was six strokes back after shooting a 70, and PGA Championship winner Keegan Bradley, who had a 72. Among the other former champions are Retief Goosen of South Africa (69), Y.E. Yang of South Korea (69), Geoff Ogilvy of Australia (73) and Jim Furyk of the United States (75). Lee Westwood of England also finished with a 69. Ramsay in lead In Sotogrande, Spain, Richie Ramsay shot a 6-under 65 Thursday to take a two-shot lead after the first round of the Andalucia Masters. Ross Fisher of England was Ramsay's closest challenger, while Frenchman Gregory Havret and Scottish golfer Stephen Gallagher both shot 68 to trail by three. Sergio Garcia was five shots back in a tie for fifth with Peter Lawrie, Scott Strange and David Drysdale on 70. Martin Kaymer started with three bogeys but recovered for a 71, to be level with Spanish playing partner Miguel Angel Jimenez and five other players, including Francesco Molinaro. Allenby ahead In Selangor, Malaysia, Robert Allenby of Australia shot an 8-under 63 Thursday to take a one-stroke lead over Jhonattan Vegas of Venezuela after the first round of the Asia Pacific Classic, the second-year event sanctioned by the PGA Tour and Asian Tour. Allenby birdied four of the first six holes and three of the last four in his bogey-free round at The Mines Resort and Golf Club. Sweden's Fredrik Jacobson opened with a 65, and Americans Bo Van Pelt, Cameron Tringale and Jimmy Walker were another stroke back.