Cameron Norrie missed out on a semi-final spot at the Barcelona Open with defeat by Tomas Martin Etcheverry.
British number one Norrie, 31st in the world, sits just one place lower than Etcheverry in the ATP rankings.
There was little to separate the pair, but the Argentine stormed through the tie-breaks to win 7-6 (7-4) 7-6 (7-1).
British number two Jack Draper also fell at the quarter-final stage of the Bavarian International, losing to American third seed Taylor Fritz.
Fritz fought back from a set down to claim a 4-6 6-3 7-6 (7-1) victory and will face either top seed Alexander Zverev of Germany or Chile's Cristian Garin in the last four of the ATP 250 tournament.