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.