So who was better, Sampras or Federer? Before you lash out, we’ll make it clear that we are not, at the moment, comparing careers. Pistol Pete wins that contest by a knockout – 14 Grand Slam titles beats eight, no matter one’s loyalties.

But Roger Federer’s fourth consecutive title at Wimbledon does present a fine opportunity to dabble in data. Sampras won four straight at the All England Club not too long ago, from 1997 to 2000, and now Federer has matched him (only Bjorn Borg and Willie Renshaw, in the late 1800s, won more consecutive titles). The staff at IBM in London have offered us match-by-match stats for Sampras and Federer’s 28-match streaks, and it’s clear that Federer has been the more dominant champion.

Consider the big picture (and the table, below). In his four years, Federer won 549 games and lost 312, a winning percentage of 63.8%. Sampras won 559 and lost 367, good for 60.4%. Federer outdid his opponents in sets 84-5 (94.4%), while Sampras put up a record of 81-12 (he played three fewer sets because Mark Philippoussis retired in the 1999 quarterfinal after winning the first set). And unlike the then 28-year-old Sampras, the 24-year-old Federer finished off his fourth consecutive title with a flourish – his most dominating performance yet. Federer won 58.5% of points at Wimbledon this year, his best percentage and better than any year Sampras had in his string of four.

No statistic more reveals Federer’s advantage than service returns. Federer has won 41.6% of return points these past four years, compared to 37.8% for Sampras. He broke his opponent’s serve 28 more times (132 to 104), an average of one more break per match. Federer has won an astonishing 49.6% of break points, compared to 39.8% percent for Sampras (not too shabby, it must be said).

On his serve, Federer nearly kept pace with Sampras, winning 72.6% of his serve points and losing his serve 25 times, compared to 75.3% and 18 breaks for Sampras. When it came time to save break points, Sampras carried the day, staving off defeat 80.9% of the time (76 of 94). Federer saved 72.8% (67 of 92). Sampras’ serve, as one might expect, proved the more explosive of the two, producing 465 aces to Federer’s 308. But it also proved more erratic. Sampras served 146 double faults, and average of 5.2 a match, compared to 50 for Federer. The defending champion served only five double faults at Wimbledon this year.

The numbers also illustrate the sharp differences in the tactics between these two men. Sampras won Wimbledon in the traditional attacking style: serving and volleying and playing more chips and slices as he pressed for an advantage at the net. Federer has killed with variety, though he has increasingly relied on his forehand rather than venturing forward.

How much of a decline has there been in Federer’s forays to the net? In 2003, he finished 20% of his points at the net, winning 64.7% of them (176 of 272). The following year, he ended 16.3% of points at net, winning 70.6% of them; these figures dropped to 15.8% (65.6% winning percentage) in 2005 and 13.4% (71% winning percentage) this year. It’s hard to argue with his results, though one gets the sense that the lack of a true rival on grass – before Rafael Nadal’s emergence this year – has made Federer feeling quite secure in playing less than risky tennis.

Perhaps surprising to some, Sampras experienced the same trend during his four-year run. In 1997 and 1998, Sampras finished 40.8% and 38.5% of points at the net. In the next two years, those percentages decreased to 25.8% and 23.1%.

Even though these two men came to the court with insurmountable tennis every single match, there were a few tests along the way.

Sampras’s most challenging opponent is no surprise. In the 1998 final, Goran Ivanisevic served 32 aces and took Sampras to five sets, 6-7(2) 7-6(11) 6-4 3-6 6-2. Sampras went five sets one other time, in a 1997 fourth round match against Petr Korda, 6-4 6-3 6-7(10) 6-7(1) 6-4. And who knows what might have happened in the 1999 quarterfinal had Philippoussis not retired? (Philippoussis continued his latest comeback yesterday with a 6-3, 7-5 victory over Justin Gimelstob in the final of Hall of Fame Tennis Championships in Newport, R.I.)

Federer has never needed more than four sets for a victory. Andy Roddick pushed him in the 2004 final, when rain interrupted play. Nicolas Kiefer, a regular troublemaker for Federer, unsettled him several times during the third round last year, taking the only set off the defending champion for the entire tournament.

Much to everyone’s surprise, Federer’s most difficult match the last four years came from Nadal, who seemed a likely candidate for a second-round loss against a qualifier before he found his game and reached the final. If Nadal had won that second set – well, never mind. Against Federer and Sampras on grass, “if” is usually as good as anyone can do.

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When Justine Henin-Hardenne announced that she would not compete in the Federation Cup semifinal between Belgium and the United States, it seemed the underdog Americans might have a chance, even without either of the Williams sisters or the injured Lindsay Davenport. Sadly, it was not to be. Kim Clijsters won both her matches, including a three-set victory over Jamea Jackson after losing the first set, and substitute Kirsten Flipkens downed Jill Craybas. For the American team of Craybas, Jackson, Vania King, and Mashona Washington, it was a valiant effort on the road, but too little. Belgium will meet Italy in the final in September, following the U.S. Open.