WIMBLEDON, England ? With time to fill during two all-day rainouts that forced Wimbledon’s third People’s Sunday in 127 years, the BBC showed old matches from such rivalries as John McEnroe vs. Jimmy Connors, and Chris Evert vs. Martina Navratilova.

If, as planned, the All England Club has a roof in place over Centre Court in 2009, the network would be able to broadcast live tennis when the inevitable showers come.

And that means future generations probably won’t get to see archived tapes of matches between two players who could be the sport’s next all-time greats, two players whose contrasting styles and personalities appear to set the stage for a career-defining series of showdowns: Andy Roddick and Roger Federer.

As McEnroe, working for the BBC, put it: “A Roddick-Federer rivalry would be sweet for the men’s game.”

Neither Roddick nor Federer got a chance to reach Wimbledon’s round of 16 Saturday. Off-and-on drizzles prevented any action on courts — other than the removal of tarps during breaks in rain, and the replacement of tarps when drops returned.

It looked almost as if a video were being shown, then rewound, shown, then rewound, accompanied by loud applause or boos, depending on which way the tarps were rolled. Play also was washed out entirely Wednesday.

By 3:30 p.m., organizers decided to scrap the traditional day of rest on the two-week tournament’s middle Sunday today. Instead, 28,000 tickets will be sold on a first-come, first-served basis starting at 9 a.m., with no reserved seats.

Within about two hours of that announcement, more than 500 people were queued up outside the grounds. The only other times a backlog of matches led to People’s Sunday, in 1991 and 1997, fans who rarely get into the All England Club brought flags and face paints, creating a livelier atmosphere.

Among the matches during today’s “Intended Order of Play,” as Wimbledon calls it: defending champion and top-seeded Federer vs. 2002 Australian Open winner Thomas Johansson, and No. 2 Roddick vs. U.S. Olympic teammate Taylor Dent.

Roddick, 21, bases his game on his serve — the fastest in tennis, which has been clocked at 153 mph — and big forehand; his volleys and backhand are improving.

Federer, 22, is as comfortable at the net as along the baseline, equipped with a strong serve and wonderful returns. He’s generally reserved, on the court and off.

Stars tend to be associated with a particular shot — Pete Sampras’ serve, say, or Andre Agassi’s return — but Federer receives praise for how well-rounded his play is.

He dropped just nine games through two matches, stretching his grass-court winning streak to 19, the longest since Sampras took 23 straight from 1998-00.

“Now things will get tougher, but I think Roger Federer is going to be picking this Wimbledon title up on more than a few occasions,” McEnroe said.

The Swiss star is 41-4 overall in 2004 with a tour-leading five titles, including a second major at the Australian Open in January.

Officials check the sky at court eighteen as rain delayed the start of play. After the second all-day rainout Saturday, organizers decided to forgo the traditional day of rest on the middle Sunday of the All England Lawn Tennis Championships and will have matches today in Wimbledon, England.

“Federer is the biggest talent from all the players I ever play in my career,” 2001 Wimbledon champion Goran Ivanisevic said. “When you look at him, you think tennis is a very easy sport, but it’s not.”

Roddick lost the No. 1 ranking to Federer early this year, and his stats are slightly less impressive: 40-8 record, three titles in 2004. Roddick’s 16-1 on grass the past two seasons, with consecutive Queen’s Club titles.

The lone loss? At Wimbledon to Federer, against whom he’s 1-5 overall. They could meet in the final this year.

Roddick “knows that the measuring stick is going to be in a lot of ways Federer,” said McEnroe’s brother, U.S. Davis Cup captain Patrick.

Working with Brad Gilbert, Agassi’s former coach, Roddick has made a concerted effort to lift his net game, in particular. Gilbert also helps the American figure out how to deal with what certain foes bring to a match.

Roddick and Federer could be trying to figure each other out for years to come.

“One of the coolest things about working with Brad was he came in, and he’s like, ‘Listen, we’re going to simplify things. You’re going to take what you’ve got, enforce it on your opponent. We’re going to study each opponent, know what they do,”‘ Roddick said. “It wasn’t all this technical mumbo-jumbo. He made it very simple.”