Britain's Kyle Edmund and Heather Watson recorded straight-set victories to reach the quarter finals at the Mexican Open, but Katie Boulter was beaten by China's Zhu Lin.

Edmund, 25, defeated Canadian fourth seed Felix Auger-Aliassime 6-4 6-4 to set up a meeting with France's Ugo Humbert or American Taylor Fritz.

Watson, 27, overcame Ukraine's Kateryna Bondarenko 7-6 (7-2) 6-2.

Meanwhile, Boulter fell to a 7-6 (7-2) 7-5 defeat by sixth seed Zhu.

After losing a disappointing first-set tie-break, 23-year-old Boulter responded well as she cemented an early break of serve in the second to establish a 3-1 lead.

But Zhu fought back to grab her second break point opportunity and draw level at 4-4 before seeing out the match with another break.

British number two Watson, ranked 69 in the world, saved two set points at 5-4 down before dominating a tie-break at the end of a topsy-turvy opening set where each player held serve just twice.

Watson made significantly fewer mistakes in the second set, racing into a 3-0 lead and eventually sealing victory with her first match point on Zhu's serve.

She will now face the winner of the all-American second-round match between Caroline Dolehide and Christina McHale for a place in the semi-finals.

British men's number two Edmund produced an impressive display to beat talented 19-year-old Auger-Aliassime.

Edmund, ranked 44th in the world, broke the Canadian world number 19's serve early in both sets and held on to his advantage relatively untroubled to continue his recent run of form.