World number three Alexander Zverev was forced to quit his French Open preparation early after a surprise last-16 defeat to Frenchman Alexandre Muller at the Hamburg Open on Wednesday.
Muller, ranked 40th globally, triumphed 6-3, 4-6, 7-6 (7/5), marking his first win over a top-five opponent.
Zverev struggled through the first set, taking just two games as Muller dominated in 34 minutes. The German bounced back in the second set, breaking Muller twice to level the match.
The final set was tightly contested, with both players exchanging breaks before heading into a tiebreak. Despite leading early, Zverev lost the final three points to Muller.
A late addition to the tournament, Zverev had hoped to build momentum in his hometown event ahead of the French Open.
However, he revealed that illness severely hampered his performance. “It was OK considering I threw up 37 times and had a fever of 39.4 degrees Celsius all night,” he said. “I was two points away from winning the match. There’s a lot to be said in my favour.”
Alexander Zverev Blames Illness for Early Exit in French Open Warm-Up
Zverev acknowledged his opponent capitalised on his weakened state, saying Muller made points last longer once he sensed Zverev’s discomfort.
Still searching for his first Grand Slam title after recent runner-up finishes at the Australian and French Opens and the 2020 US Open, Zverev has had a mixed 2025.
He won the Bavarian Open in April but was knocked out in the Rome quarter-finals last week.
Zverev was the defending Hamburg champion and finalist last year, but was seen as the favourite following world number one Jannik Sinner’s late withdrawal.
Earlier on Wednesday, American second seed Frances Tiafoe and fourth seed Francisco Cerundolo also suffered upsets in the tournament.