It was one of the most impressive runs in tennis history, but all records are meant to be broken.
In losing to Sweden's Robin Soderling Tuesday in the French Open quarterfinal, Roger Federer's run of 23 consecutive appearances in a Grand Slam semifinal or better came to an end.
In losing to Soderling for the first time in 13 head-to-head matches, Federer could lose the No. 1 world ranking he'd worked so hard to get back. If Rafael Nadal wins the French Open, he will retake the No. 1 spot.
So the ping pong game of "Who's No. 1?" continues.
Federer's streak of Slam semis was more than twice as long as any other streak of its kind.
Ivan Lendl and Rod Laver were both able to put together 10-tourney streaks.
The other streak that could end with Federer's loss is his second run at No. 1.
Rafael Nadal will take over the No. 1 world ranking after 48 weeks on top by Federer if he wins at Roland Garros.
Nadal, the speedy clay court specialist, first took over the No. 1 spot from Federer on Aug. 18, 2008.
He spent 46 weeks on top, the 13th-longest run at No. 1, tied with Bjorn Borg.
Soderling is no stranger to crashing the party of this all-time rivalry.
The Swede derailed a possible Nadal-Federer final at Roland Garros last year with a fourth-round upset of Nadal.
It was a major factor in Nadal losing crucial ranking points that led to Federer regaining the world's No. 1 ranking back a month after the French Open ended.
This is Federer's second run on top of the world rankings.
His first string was historic.
Federer was No. 1 for 237 weeks from Feb. 2, 2004 to Aug. 17, 2008.
That's more than four years atop the tennis world, by far the longest streak of all time.
Jimmy Connors has the second-best streak at No. 1 with 160 weeks.
Federer could tie Pete Sampras for the longest combined weeks at No. 1 for his career if Nadal loses in Paris.
Otherwise, he'll have to wait awhile. Federer has already broken Sampras' Grand Slam titles record with 16 titles to Sampras' 14.
Sampras was No. 1 for 286 total weeks in his career; Federer currently sits at 285.
Sampras is still is ahead of Federer in total Slam tournament wins, 200-199.
If Federer and Nadal had both reached the final, it would've been the eighth time the two had met in a Grand Slam final.
As it is, they are still tied for the most Slam final matches ever with Bill Tilden and Williams Johnson.
It's been a six-year-plus run of Federer or Nadal at No. 1.
The last player other than these two to hold the coveted spot atop the men's tennis world is Andy Roddick, who owned the spot for 13 weeks from Nov. 2003 to Feb. 1, 2004.
Federer and Nadal have owned the No. 1 spot for at least 46 straight weeks over the last three reigns.
Before that, the title switched hands five times over 40 weeks.
Roddick (13 weeks), Juan Carlos Ferrero (8), Andre Agassi (12), Lleyton Hewitt (5) and Agassi (2) passed the honor around from April 28, 2003 to Feb. 1, 2004.
Thanks to the way the ranking system works, Federer faces an uphill climb to get his hands back on the No. 1 ranking before the end of the year — if Nadal wins the title at the French.
Federer must defend his points at Wimbledon and the U.S. Open whereas Nadal had early exits at both spots and has fewer points to defend.
Nadal could actually gain on Federer simply by advancing to the later rounds of each Slam.
If Federer finds himself as the hunter rather than the hunted, it's far from impossible for Federer to get back his No. 1 spot by the end of the year.
He'll simply need to play his top tennis and hope Nadal plays worse at the remaining Slams than he did last year.
If Federer ends the year at No. 1, he'll tie Sampras with six times at No. 1.
He's currently tied with Connors with five.