Stan Wawrinka failed to convert 12 break points as he lost to Sam Querrey in the second round of the Fever-Tree Championships at Queen’s.
The Swiss, who has dropped to 261st in the world after injury, was beaten 7-5 6-7 (3-7) 6-1 by the American.
Wawrinka, a three-time Grand Slam champion, wasted seven set points at 5-4 in the first set and only capitalised on one of 13 break points in the match.
Querrey dominated on serve, hitting 25 aces as he closed out victory.
Fifth seed and 2010 champion Querrey will face the winner of Wednesday’s match between Croatian sixth seed Marin Cilic and Luxembourg’s Gilles Muller.
American Frances Tiafoe reached his first ATP grass-court quarter-final with a 6-4 2-6 6-4 win over Leonardo Mayer of Argentina.
In the ATP grass-court tournament in Halle, Karen Khachanov of Russia beat Japanese seventh seed Kei Nishikori 6-2 6-2 to go through to the quarter-finals.
Khachanov, who reached the fourth round at this year’s French Open, will next face Roberto Bautista Agut after the Spaniard beat Dutchman Robin Haase 4-6 7-5 6-4.
The top seed in Halle is Swiss eight-time Wimbledon champion Roger Federer, who plays Frenchman Benoit Paire on Thursday for a place in the last eight.