Fed Cup captain Anne Keothavong could do little to hide her bursting pride as Great Britain battled past Croatia to progress to the World Group II play-offs in April.
Having already breezed past Portugal, Latvia and Turkey this week, Keothavong's team faced a tougher challenge in the form of Croatia, who came into the tie having dropped just a solitary set in their previous two ties.
It looked as though the match was Great Britain's for the taking in Tallinn, however, when Heather Watson sealed a straight sets victory in her singles rubber against Donna Vekic.
Watson had not dropped a set all week, and ensured that run would continue as she swept past her opponent to triumph 6-2 6-4.
But a shock result was in store for world number ten Johanna Konta when she faced Ana Konjuh in the second singles tie - victory in which would have given Great Britain an unassailable lead.
A 6-4 6-3 win for Konjuh took the tie into a decisive doubles match, and while Laura Robson and Jocelyn Rae had been the first choice all week, Keothavong brought in Watson and Konta in a late reshuffle.
They were broken twice in the opening three games, before eventually losing the first set 6-4.
British number one Konta required treatment on her ankle prior to the start of the second set, but Keothavong's substitution paid dividends as the duo levelled, before Konta and Watson secured the decisive break on their way to a 4-6 6-4 6-3 victory.
"I'm absolutely ecstatic," said Keothavong. "It's been a real emotional rollercoaster, but the way the girls performed today and throughout the whole week, I'm just so proud of them.
"It wasn't easy today against Croatia with it coming down to the deciding doubles.
"It was tight, everyone was on the edge of their seats. But they fought their hearts out and played with so much passion out there."
Great Britain will now enter the play-offs on April 22-23 as they look to reach the World Group II.
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