Katie Boulter beat Australia’s Olivia Gadecki in straight sets to ensure Great Britain reached the United Cup quarter-finals in Sydney.

Boulter knew a straight-set victory from any of the three rubbers against the hosts would take GB through as Group F winners.

In the first match of the tie, Boulter won 6-2 6-1 inside 70 minutes to put GB 1-0 up and secure qualification.

Britain had beaten Argentina 2-1 in their opening tie at the event on Tuesday.

“I’ve been trying to avoid all the stats on all this but we were at dinner with [former British number one] Laura Robson last night, and she thankfully told me I had to win in straight sets,” Boulter said.

“So I was feeling the pressure from last night.”

Australia’s Alex de Minaur, who is Boulter’s fiance, faces Billy Harris in the men’s singles before the mixed doubles, but neither result will have an impact on GB’s progression.

Boulter is scheduled to play in the mixed doubles, but De Minaur is not.

Alexander Shevchenko helped Kazakhstan reach the quarter-finals as they knocked out defending champions Germany, who were without world number two Alexander Zverev because of a biceps injury.

Poland also qualified, with Iga Swiatek beating the Czech Republic’s Karolina Muchova.