Russian Daniil Medvedev reclaimed the world number two spot from Rafael Nadal in the latest ATP rankings released on Monday, with no Americans in the top 30 for the first time.
Nadal was knocked out of the Madrid Open in the quarter-finals last week by eventual champion Alexander Zverev, raising questions about his form ahead of his bid for a record-extending 14th French Open title.
That would also see him break Roger Federer’s all-time men’s record with a 21st Grand Slam singles triumph.
German Zverev remains in sixth place despite his first Masters title in three years.
Taylor Fritz is the highest-ranked American at 31st — the first time the US have not had a player in the top 30 since the ATP rankings were created in 1973.
Madrid Open runner-up Matteo Berrettini jumped up one spot to world number nine.