Cameron Norrie suffered an agonising defeat to Spain's Roberto Carballes Baena in the second round of the Millennium Estoril Open.
The British number three was looking to make his first ATP Tour quarter-final and led 5-2 in the deciding set before holding a match point in the 10th game but Carballes Baena fought back to win 5-7 6-2 7-6 (7/1).
His first-round victory over sixth seed Robin Haase might yet be enough to see 22-year-old Norrie break into the top 100 on Monday only a year after turning professional.
British number one Kyle Edmund plays Portugal's Joao Sousa in the last eight on Friday.
Top seed Kevin Anderson went out to Greece's Stefanos Tsitsipas in Portugal. Tsitsipas prevailed 6-7 (3/7) 6-3 6-3.
Marin Cilic got back to tennis after his wedding only to suffer a shock defeat to Malek Jaziri at the Istanbul Open.
Top seed Cilic got married last weekend but could not transfer that honeymoon feeling into his day job, with world number 78 Jaziri prevailing 6-4 6-2 in Turkey.
Tunisia's Jaziri broke big-serving Cilic five times en route to topping the world number four, to book a quarter-final berth against seventh seed Jiri Vesely.
Former US Open champion Cilic was left to rue a knee issue, while still laying all the plaudits on Jaziri.
"It was my first match and Malek played great," Cilic told the ATP Tour website.
"I had issues with my knee, so I wasn't serving that well. But all the credit to Malek, I tried to play aggressively and I didn't want to slow the pace down or be defensive."
Jaziri admitted he feels he is gaining in strength week by week, ahead of his last-eight meeting with Vesely.
"I'm really happy to win," Jaziri told the ATP Tour website.
"It's a very important match in my career. I've worked really hard to get this win over a top-five player. It wasn't an easy match as I needed to be focused every point, to keep my error count down.
"I feel as if I am improving my tennis and fitness every week."
Elsewhere in Istanbul, Thomas Fabbiano saw off second seed Damir Dzumhur 6-2 0-6 6-2, while Jeremy Chardy dispatched Dusan Lajovic 4-6 7-6 (7/3) 6-2.
Roberto Bautista Agut eased past Norwegian wild card Casper Ruud 6-4 6-3 at the Munich Open to set up a quarter-final with Philipp Kohlschreiber.
Kohlschreiber eased past compatriot Mischa Zverev 6-2 6-2, while Maximilian Marterer saw off third seed Diego Schwartzman 6-4 6-2 and Marton Fucsovics beat Marco Cecchinato 7-6 (7/5) 6-1.