Jack Draper reached the quarter-finals of the BNP Paribas Open in Indian Wells with a straight-sets victory over No3 seed Taylor Fritz.
Draper turned the match in his favour with seven successive games from late in the first set before he survived a late stumble to win 7-5, 6-4.
Serve dominated the first 10 games, the British No1 seizing his only break opportunity in the eleventh game and serving out to win the set.
Draper, seeded 13th in Indian Wells, broke twice more as he surged into a 4-0 lead in the second set.
He finally stumbled when serving for the match at 5-2 as a double fault handed the American former champion a break, but a pair of aces propelled him to victory at the second attempt.
"It is the best match I have played here so far in the three years I have been here," Draper said
"There were a few moments here and there which I was brave, which I spoke to my coach about before the match.
"Taylor is such an amazing player, so to come through in the way I did I am very proud of that."
Draper faces Ben Shelton in the last eight after the American No11 seed beat Brandon Nakashima 7-6, 6-1.
Ninth seed Alex de Minaur was knocked out in straight sets by Francisco Cerundolo and the Argentinian will face Grigor Dimitrov or Carlos Alcaraz in the last eight.
Sonay Kartal's run ended at the last-16 stage of the women's event as she was beaten 1-6 2-6 by Aryna Sabalenka.
The British No3 reached the main draw at the competition as a lucky loser following Sloane Stephens' withdrawal and after beating Polina Kudermetova in the previous round, she was rewarded with a clash against world No1 Sabalenka.
Although Kartal broke to win the first game of the opening set, Sabalenka quickly settled into the match and powered away to book a clash with Liudmila Samsonova, a 6-0 6-4 winner over sixth seed Jasmine Paolini.
Wildcard Belinda Bencic secured her spot in the quarter-finals, coming from behind to earn a 3-6 6-3 6-4 win over third seed Coco Gauff. She will face Australian Open champion Madison Keys, who beat Donna Vekic 4-6 7-6 6-3.
