A day after losing the men's French Open final, world number four Stefanos Tsitsipas withdrew on Monday from this week's ATP grass court tournament in Halle with exhaustion.
"Unfortunately, I cannot play in Halle because of the exhaustion after the last two tournament weeks in Paris and yesterday's five-set final," said the 22-year-old.
Tsitsipas, the first Greek player to reach a Grand Slam final, lost 6-7 (6/8), 2-6, 6-3, 6-2, 6-4 to Novak Djokovic in the men's final at Roland Garros on Sunday.
On Monday morning, Tsitsipas revealed he had only learnt of the death of his grandmother just before playing Djokovic.
His run to the French Open final moved Tsitsipas up one place to fourth in the world rankings.
Swiss tennis star Roger Federer is ranked fifth in Halle and will start his grass court season later on Monday when he faces qualifier Ilya Ivashka of Belarus.