London - Roger Federer was well short of his best as the seven-time Wimbledon champion advanced to the second round with an uninspired 7-6 (7/5), 7-6 (7/3), 6-3 victory over Argentina's Guido Pella on Monday.
Federer has been plagued by injury problems this year and the world number three lacked rhythm and confidence in his opening match at this year's grass-court Grand Slam.
The 34-year-old, without a major title since 2012, will play British qualifier Marcus Willis for a place in the last 32.