World men's tennis number one Roger Federer has began his quest for a sixth consecutive US Open title by defeating US teenager Devin Britton in straight sets in a first-round match in New York.
The Swiss superstar advanced in 88 minutes to a second-round match against Germany's 65th-ranked Simon Greul.
Britton, an 18-year-old US wild card who lost his only prior top-level match last month at Indianapolis, was outclassed from the start.
The 1,370th-ranked US college champion dropped the first set in 18 minutes, battled back in the second and broke Federer in the seventh game of the final set only to have Federer break back twice.
Federer completed a career Grand Slam by winning the French Open in June and set an all-time record with his 15th Slam title in July at Wimbledon.
Federer, a semi-finalist in each of the past 21 Grand Slam events, has won 61 career titles and nearly 75 million dollars in prize money, taking trophies at Madrid and Cincinnati this year in addition to his two Slam crowns.
After reclaiming the top ranking from Rafael Nadal with his Wimbledon title, Federer can keep the top spot by reaching the US Open's round of 16. An earlier exit opens the door for Nadal or Britain's Andy Murray to become number one.
Federer has not lost a match on the Flushing Meadows hardcourts since 2003, when David Nalbandian beat him in the fourth round.