Rafael Nadal's shock humbling at the hands of Alexander Zverev at the Madrid Open has seen him drop in the ATP rankings.
Following his Barcelona Open title, many thought Nadal would prove too strong in Madrid in the build-up to the French Open.
But the Spaniard fell to eventual champion Zverev at Madrid and has also dropped to World No.3 after the tournament.
Russian Daniil Medvedev moved up to World No.2, while Dominic Thiem remained the World No.4.
Novak Djokovic extended his record run as the male player with the most weeks as World No.1 to 320 weeks.
Nadal's second defeat on clay this season, after his Monte Carlo loss, prompted the Spaniard to address his form leading into Roland Garros.
"I took steps forward, but when you go up a staircase, there are times when it happens that you take a step back, that's what happened today," said five-time Madrid champion Nadal.
"It's a week where there were a lot of positive things. I'm leaving Madrid with good feelings in general, and the bad one having played a match like today.
"Now, what is the goal before Roland Garros? Go to Rome (for next week's Italian Open) and win, that's all."
US men fall out of World rankings
For the first time since 1973, since the introduction of computerised rankings, there is no American in the World Top 30.
A first-round loss in Madrid by Taylor Fritz, the highest-ranked American, dropped him one spot to No.31 in the rankings.
John Isner, who was defeated in the quarterfinals in Spain, climbed five spots to No. 34.
The last American man to be ranked No.1 was Andy Roddick from November 30, 2003 to February 1, 2004, after he won the 2003 US Open.
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