Los Angeles  - Father-of-twins Roger Federer probably can't wait to return to tennis, according to the wisdom of fellow parent Pete Sampras.

"He'll hit the road as soon as he can," joked Sampras Monday during an appearance at the Los Angeles Open. "I'm sure he will start playing 40 weeks a year."

Sampras, 37, the father of boys aged three and six, said in a more serious vein that despite Federer's wife Mirka giving birth to a pair of girls last Thursday, elite tennis life would go on for Swiss the world number one.

"I can't see Roger changing diapers at 4 am at the US Open. I'm sure they will have help. I don't think fatherhood will affect his game.

"It's a life-changer, but he's focused on his tennis. He'll keep doing what's he's done the past few years."

Sampras was on hand in the Royal Box at the Wimbledon final in London three weeks ago when Federer beat Andy Roddick to lift a 15th Grand Slam singles title and break the longstanding Sampras mark set in 2002 when he won the US Open over Andre Agassi and retired on the spot.

The flying London visit was a rare trip for the former great, who is perfectly content to stay in LA where he has a home and family life and golf courses nearby. "Wimbledon was my home for a while and I enjoyed it. To be back there was pretty cool."

"Roger will go on to win more than 15 majors," Sampra sadded, "I think the future of the sport is healthy."

The American admitted that he perhaps never thought he'd see the day his mark was broken.

"When I was done, I felt I'd put up some numbers no one would touch. But little did I know Roger would surpass me in seven years," Sampras said.

"Records are made to be broken. I believe in that. I also can't do anything about it. My days are over but I'm content with my 14 [titles]. "I'm still amazed at what Roger has been able to do. It's incredible."

On court at the ATP event, which is part of the run-up to the US Open, Australian Chris Guccione advanced to the second round over American Kevin Kim 6-4, 6-1.

Jesse Levine beat fellow American Bobby Reynolds 6-2, 6-3, while Florida veteran Vince Spadea went down 6-0, 6-0 to Robert Kendrick in the fourth "double bagel" this season on the ATP.

German Tommy Haas, champion in 2004 and 2006, heads the field. (dpa)