British number two Aljaz Bedene upset eighth seed Jeremy Chardy to reach the second round of the Valencia Open.
Bedene, at a career-high ranking of 48, swept past France's world number 31, winning 12 of the last 15 games to take a 3-6 6-2 6-1 victory.
The Slovenia-born 26-year-old, who gained UK citizenship in March, next plays Canadian Vasek Pospisil.
"I need to be ready for his big serves - not just to put in a return but to make something of it," said Bedene.
"He's a great volleyer as well and has a great forehand, so I need to be active all the time and not lose serve as I did so easily in the first set today."
Bedene won his only previous match against world number 43 Pospisil in Miami last year.
Kyrgios knocked out
Australian Nick Kyrgios was knocked out of the tournament in a 6-4 2-6 7-6 (7-3) first-round defeat by German qualifier Daniel Brands.
World number 30 Kyrgios was 4-1 up in the first set but lost it and, despite comfortably winning the next, was beaten in a tie-break in the decider.
"I think the key was to stay calm and just to focus on the important points," said 170th-ranked Brands, who will next play David Ferrer. "I think I played some good points and a really good match."