Paris, France: Fourth seed Alexander Zverev was dumped out of the Paris Masters on Wednesday by Dutchman Robin Haase in a 3-6, 6-2, 6-2 second-round defeat.
The 20-year-old German lost his composure after easing through the first set, as his bid for a third Masters title of the season was abruptly ended at Bercy Arena.
It was the world number 43 Haase's first-ever win over a top-five player.
Zverev will next play at the It was the world number 43 Haase's first-ever win over a top-five player. in London later this month, while Haase goes on to a last-16 tie against either Joao Sousa or 13th seed Juan Martin del Potro.
Zverev was put under pressure from the off as he was forced to save four break points in the opening game, but he broke in game four and served out to take a one-set lead.
The unseeded Haase started to mix up his game well at the start of the second set, though, and reeled off three straight games as Zverev became frustrated.
The 30-year-old continued to send winners past his opponent and broke serve again to force a decider.
Zverev, the youngest player to break into the world's top five since Novak Djokovic 10 years ago, continued to struggle to make any impact on the Haase serve as he fell 3-2 behind in the third set.
Haase grabbed the crucial break with a stroke of luck from the net cord, before completing one of the biggest victories of his career with a run of four games on the spin.