WASHINGTON (AP) Venus Williams lost an Olympic tuneup Monday during a World Team Tennis match attended by first lady Michele Obama.

Williams, playing for the Washington Kastles, lost 5-0 to the Boston Lobsters' Irina Falconi in the women's singles portion of the match. In the best-of-five games format, Williams - ranked No. 68 - struggled with her serve, double-faulting several times to the 85th-ranked Falconi.

Obama and daughters Sasha and Malia, who entered Kastles Stadium to applause, saw Williams help the Kastles to 5-1 mixed doubles and 5-1 women's doubles victories, but left before Williams lost her singles match.

I think I just cooled down, and I couldn't quite get started back up again,'' Williams said.In team tennis, you really have to keep your energy up. You have to manage the stop and go. I didn't manage it that well.''

Williams is trying to prepare for those types of challenges at the London Olympics, which begin July 28 for tennis. She called the 2012 Games ``the ultimate achievement'' for her.

This Olympics is more exciting for me,'' she said.All the other ones, I didn't have to worry whether or not I would make it. I was on top of the rankings. I didn't have any problems. It was, for a lack of a better word, for granted. But this time, I had to fight so hard for it, just to get in contention and come back from so much.''

Williams, who won singles gold in 2000, has been trying to mount a career comeback after being diagnosed with an autoimmune disease.

``I've been training to bring home medals for the U.S., and I would love if the medal is gold-colored,'' she said.

Serena Williams is scheduled play for the Kastles on Sunday.