Cameron Norrie stunned fourth seed Diego Schwartzman to reach the quarter-finals of the Mexico Open, while Johanna Konta also won through to the last eight.
British No 2 Norrie had already beaten Japan's Yoshihito Nishioka in three sets to reach the last 16, but took the notable scalp of the Argentine world No 25 to set up a quarter-final showdown with Mackenzie McDonald.
Norrie was down an early break in the opening set, but fought back to force a tiebreak and then put himself in the lead.
The pair then traded breaks in the second, with Schwartzman eventually claiming the edge to draw level, but it was Norrie who came out on top in the decider to seal a 7-6 (7-5) 4-6 6-3 win.
In the women's draw, Konta also continued her run on the hard courts, claiming a spot in the last eight following a straight sets win over Russia's world No 167 Varvara Flink, but fellow Briton Katie Boulter was forced to withdraw.
British No 1 Konta, seeded eighth, dominated from the start, breaking her opponent in the first game of the match, before clinching a 6-4 6-1 win in an hour and 23 minutes to seal a quarter-final date with third seed Donna Vekic.
Boulter did not fare as well. Trailing Sonya Kenin 6-4 4-1, the British No 2 was forced to retire from her second-round match
Meanwhile, Kyle Edmund posted his first win of 2019 by beating Tommy Robredo in the second round of the Oracle Challenger Series at Indian Wells.
The world No 27, who was given a bye in the first round, swept past his Spanish opponent 6-4 6-4 in an hour and 23 minutes.
The victory comes after a disappointing start to the year for Edmund, who fell to Tomas Berdych in the first round of the Australian Open last month.
Dan Evans, who narrowly missed out on his first ATP title at the weekend, claimed a 6-4 7-5 first-round win against Maxime Cressy while in the women's event, fellow Briton Heather Watson was dismissed by China's Han Xinyun 6-4 7-6 (7-4).
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