Dan Evans pulled off his biggest win since Wimbledon to keep Great Britain in the inaugural ATP Cup in Sydney.
Needing to beat Belgium to stay alive following their opening day Group C defeat by Bulgaria, Britain got off to the worst possible start when Cameron Norrie suffered a surprise straight-sets defeat to veteran Steve Darcis.
However, British number one Evans defeated world number 11 David Goffin 6-4 6-4 to send the tie into a decider rubber and doubles pair Jamie Murray and Joe Salisbury duly obliged with a 6-3 7-6 (7) win over Sander Gille and Joran Vliegen.
Evans, who let slip a one-set lead against Bulgaria's former world number three Grigor Dimitrov on Friday, held the upper hand throughout most of his first ever meeting with Goffin despite winning only 57 per cent of his service points.
He secured all three of his break points in the first set but was broken twice himself as both men struggled to hold serve.
The 29-year-old Briton eventually served out the first set and broke his opponent twice early in the second to race into a 4-0 lead.
However, Goffin then reeled off three games in a row to stop the rot and set up a nerve-jangling finish.
Evans squandered four match points and was forced to save a break point before eventually prevailing after one hour and 48 minutes to secure a first top-20 win since eliminating Nikoloz Basilashvili at Wimbledon last year.
Murray and Salisbury lost their deciding match against Dimitrov and Alexandar Lazarov on Friday but made amends at Ken Rosewall Arena with a battling victory in which they denied their opponents a single break point.
The Britons broke in the fourth game and served out the first set 6-3 but there was little to choose between their pair in the second set.
Gille and Vliegen led 3-0 and 5-3 in the tie break before Murray and Salisbury twice levelled and the Britons squandered one match point before finally taking the breaker 9-7.
Earlier, Darcis needed only one hour and 12 minutes to beat world number 53 Norrie 6-2 6-4.
The 35-year-old Belgian has announced his intention to retire after the Australian Open but earned his best win since beating Adrian Mannarino at an ATP Challenger Tour event in Lisbon last May.
The new 24-nation tournament features six groups of four teams. Each country plays three round-robin ties which are comprised of two singles matches and one doubles.
Bulgaria earlier clinched their place in the last eight by defeating Moldova 2-1.
Australia's Alex De Minaur rallied from a set down to win for the second time in a battle of 20-year-olds as he overcame Canada's Denis Shapovalov 6-7 (6) 6-4 6-2 to clinch the tie for the home country.
Earlier, John Millman more than adequately filled in for an injured Nick Kyrgios, who was sidelined by back pain, to beat Felix Auger-Aliassime 6-4 6-2 and doubles pair Chris Guccione and John Peers finished off the sweep.