The GB Fed Cup team danced around in celebration after Boulter sealed victoryGreat Britain v Kazakhstan - Fed Cup World Group II play-offVenue: Copper Box Arena, London Dates: 20-21 AprilCoverage: Live commentary on BBC Radio 5 Live and live text commentary on BBC website
Great Britain ended a 26-year wait for Fed Cup promotion when Katie Boulter came from behind to beat Zarina Diyas to seal a play-off win over Kazakhstan.
British number one Johanna Konta had put GB one win away from World Group II with a stunning comeback in a 4-6 6-2 7-5 win over Yulia Putintseva.
Boulter trailed by a set and a break - and was troubled by a back problem - before beating Diyas 6-7 (1-7) 6-4 6-1.
The win put Britain 3-1 up in the best-of-five tie at London's Copper Box.
Celebratory scenes as Boulter finishes the job
After watching Konta come from 4-1 down in the deciding set to beat Kazakh number one Putintseva, Boulter knew victory in her match would seal the tie for Britain.
Boulter admitted she was "struggling physically" during her defeat by Putintseva on Saturday and although she swiftly took a 2-0 lead in the opening set, she repeatedly sat with a hot water bottle on her back during changeovers.
Diyas - who Konta needed two hours and 38 minutes to beat on Saturday - started to find her groove and responded to take the set to a tie-break.
Boulter admitted Saturday's dramatic defeat - which came despite her holding three match points - would stay in her mind "for a long time" and she seemed nervous - only picking up one point as Diyas comfortably won the tie-break 7-1.
The Kazakh gained the advantage in the second set too but was seemingly distracted by a car alarm seconds before double-faulting and allowing Boulter to break back at 2-2.
The addition of a few drums in the British crowd - to compete with the noisy Kazakh band that had been providing a soundtrack to the action - built a more intimidating atmosphere and Boulter thrived off their support, breaking again late to win the set.
Diyas and Boulter had already suffered three-set defeats this weekend but the Briton was determined not to lose another.
The 22-year-old British number two was quickly 2-0 up before she held off a break point in the third game of the third set - prompting a standing ovation from the home fans.
A lucky net cord helped bring up break point for Boulter at 3-0 up but Diyas saved it with a thumping serve.
That only delayed Boulter's move to increase her advantage as she turned up the gears to make it 5-1.
Konta, fresh from her victory, joined Heather Watson, Katie Swan and Harriet Dart on court ready to celebrate.
And Boulter, on her third match point, threw her arms up in celebration as the crowd erupted in joy.
The British team leaped over the hoardings to run over to Boulter, and the team hugged before dancing around in a circle on court.
More to follow.
