For most of a decade, Roger Federer or Rafael Nadal have been the best tennis players in the world. From Wimbledon 2003 through the French Open this year, they won 26 of 33 grand-slam championships.

It seemed as if the only times they lost … were to each other.

Even here at the end of 2011, Rafael Nadal is ranked No. 2 in the world and Roger Federer is ranked No. 3.

Both are playing in Abu Dhabi as part of the Mubadala World Tennis Championship, and both played in the semifinals today … and both lost.

Which leads me to wonder … when was the last time Roger and Rafa lost on the same day?

First, Federer was annihilated by Novak Djokovic, 6-2, 6-1, in 44 minutes. (I asked Roger, afterward, if he could recall the last time he lost 2-and-1 in any match in which people were keeping score, and he said: “No.”)

An hour later, gritty little David Ferrer routed Nadal 6-3, 6-2.

The two biggest names in tennis, out of a tournament within about two hours.

Perhaps I shouldn’t raise the question of “last time they lost on the same day” if I can’t answer it … and I can’t. This tennis event is not an official ATP event, and we don’t have media guys around we could ask for a stat check …

I’m thinking it hasn’t happened since Nadal became a serious player, in 2005. Though it may not happened for a few years before that, too, because Nadal was probably losing in the earlier rounds of ATP events and Federer already was ruling the world.

If you had seen the matches, it wouldn’t have seemed so strange — or even unexpected. Federer and Nadal entered the little tournament here at the semifinal stage; neither had played a competitive match in weeks.

Meanwhile, Djokovic, ranked No. 1 in the world since July, already looks very sharp. Federer agreed. And Ferrer is ranked No. 5, and Nadal had hardly played since hurting his left shoulder while helping Spain win the Davis Cup back in the first week of the month.

Fans here were a little disappointed. A year ago, Nadal and Federer met in the final here and played a 7-6, 7-6 match — with Rafa winning.

The consolation here is … they will meet again this year on the final day. Albeit in the third-place game.

Here are the fast-and-terse stories I did on the Rafa-Roger defeats, for The National.