This weekend's Fed Cup quarterfinals pitting the United States versus Belgium in Delray Beach, Fla., could be subtitled "Bowling with the Williams sisters." Bowling the way kids do at birthday parties, that is, with those big rubber bumpers installed in the gutters to keep the ball going toward the pins.
In other words, it looks like a can't-miss: two of the world's best-known and most-talented players playing singles against No. 132 Kirsten Flipkens and No. 227 Caroline Maes.
Neither Flipkens nor Maes has a WTA title on her résumé. Venus and Serena Williams have a combined 62 titles, including 13 Grand Slam championships, and career earnings in excess of $34 million.
As if the divide could yawn any deeper, the sisters are also on a roll. They're back in the top 25 (Serena at No. 11, Venus at No. 22) after a joint period of prolonged inactivity last year.
Serena has hoisted the two biggest trophies of 2007 thus far, at the Australian Open and Sony Ericsson Open. Venus hasn't been as dominant but did win her first tournament out of the chute, in Memphis. She fell to Maria Sharapova in a sloppy, windblown third-round match in Miami, then reached the quarterfinals and semifinals in the two U.S. clay-court events since.
Yet despite the competitive disparity, the Williams' appearance at Fed Cup has symbolic value for American tennis, said Billie Jean King, former team captain and still passionate observer.
"They truly transcend our sport," King said on a recent visit to Philadelphia to promote World Team Tennis, which both sisters will play this summer. "It's so big, so great when they're playing well and enjoying life on the tour. It's the way they play, the star power. Also, the fact that they're women of color is important. It sends a great message for our sport that diversity is important, that multiculturalism is important.
"There are so many positive messages. It's great that Serena has a lot of muscles and Venus is skinny because it's two different body types who bring so much. You can have different looks and still be good at what you do."
Without King's own star power, the sisters might not have played the women's equivalent of the Davis Cup. King was the one who first enticed them to represent the U.S., and she mentored current captain Zina Garrison. Venus and Serena have emphasized their personal loyalty to both women.
"I usually play Fed [Cup] because I love Zina, and I play for Zina," Venus said in Miami last month. "Definitely. I like playing for the U.S., and I really love Billie Jean, and I'd play for her, too. Those are two women that I definitely play for. That's why I play."
The sisters' last joint Fed Cup appearance was in 2003, when they paired up for doubles against the Czech Republic. Venus is 13-3 in Fed Cup play. Serena, who is a perfect 6-0 in Fed Cup competition, hasn't played since Garrison's tenure began in 2004.
"I wanted to play Fed Cup a couple years ago, once Zina became coach for the first time, but for some reason I've just never been able to play," Serena said during her title run at the Sony Ericsson. "Also, since it's in the United States, it's always a much easier choice and a little easier decision. I look forward to playing for Zina and just going with that."
Another factor influencing the Williamses is their stated desire to play at the Olympic Summer Games in Beijing next year. By playing against Belgium, both sisters will have met the International Tennis Federation qualifications needed to be selected for the Olympic team.
Like their Davis Cup counterparts, Fed Cup captains have struggled to attract top players in recent years. World No. 1 Justine Henin of Belgium bowed out of the event even before respiratory problems caused her to withdraw from the two U.S. clay-court events that preceded the Fed Cup weekend. No. 4 Kim Clijsters, who has not just one foot but most of her body out the door as she winds down her career, also declined.
That left new Belgian captain and former WTA pro Sabine Appelmans in much the same situation Garrison faced a year ago, when the Williams sisters and Lindsay Davenport were idled by injury. Garrison selected veteran Jill Craybas and young hope Jamea Jackson for singles and saw her choices vindicated when the U.S. upset Germany.
Along with Flipkens and Maes, Appelmans chose two teenagers, 422nd-ranked Yanina Wickmayer and Tamaryn Hendler, currently No. 22 in the world junior rankings.
"Nobody expects us to win," Appelmans said Wednesday. "I think every point we win is good. But, of course, we want to do better than that. I told the girls also we have to go out there and believe we can do this. In tennis, everything is possible."
Garrison, who defeated Appelmans in a Fed Cup match 17 years ago, insisted the U.S. players are taking nothing for granted.
"They're all very professional," she said. "They understand it's a 50/50 chance when you go out there. We've already talked about being prepared, taking care of business, not looking ahead."
Two singles matches will be played Saturday and two more Sunday before the doubles match, which is played at the end rather than in the middle as it is in Davis Cup.
World No. 1 doubles specialist Lisa Raymond and 83rd-ranked Vania King, an 18-year-old in her first full professional season, are expected to team up for what most likely will be a meaningless match.
Ticket sales have suffered because of the pullout of the two top Belgians. The U.S. Tennis Association announced Wednesday that it would offer discounted $10 tickets for each weekend day.
The U.S. players have said repeatedly that they understand Henin's and Clijsters' decisions to opt out of the competition.
"The calendar is just so strange in the way that sometimes they put Fed Cup," Serena Williams said. "It's at the worst dates, the hardest weeks. It's like fitting an extra week of tennis in there."
This weekend's winner will face Russia or Spain the week after Wimbledon ends in July. The U.S. team has won a record 17 titles since 1963, most recently in 2000.
Bonnie DeSimone is a freelancer who contributes frequently to ESPN.com.