Colin Fleming and Ross Hutchings ensured Great Britain earned promotion to the Europe/Africa Group One of the Davis Cup after an impressive doubles performance against Hungary.
The experienced doubles pair beat Attila Balazs and Kornel Bardoczky 6-3 6-4 6-4 at Glasgow's Braehead Arena.
The win by the US Open and Wimbledon quarter-finalists gave GB an unbeatable 3-0 lead in the tie.
Singles wins by Andy Murray and James Ward on Friday had put GB in control.
Although Balasz looked a much better player than he had during his singles defeat by Ward while Bardoczky was also capable of hitting some searing winners, overall the British pair always appeared to have the edge.
There were some shaky moments in the first set, particularly on the Fleming serve, but the Scot held on and the crucial break was secured in the eighth game.
Hutchins had lost all four of his previous Davis Cup matches, including a rubber with Fleming against Ukraine two years ago, but both players have improved significantly since then.
Britain began the second set by winning eight straight points but the Hungarians stayed in contention and it was not until the fifth game of the third set that Fleming and Hutchins broke again, celebrating with a Bryan brothers-style chest bump.
And that proved enough for the pair to secure victory, Fleming holding his serve with ease in the final game to give Leon Smith's side a fourth straight win as Hungary went the same way as Turkey, Tunisia and Luxembourg.
Smith's side will return to the second tier of the competition next year for the first time since 2009, where much tougher challenges will await in Wednesday's draw.
But the Scot knows that for Britain to have a chance of staying in Group One, or even getting higher, Andy Murray must play.
The world number four has always stated his desire to represent his country but, with the ties often coming at busy periods of the season, he has not always felt able to commit.
Smith said: "In terms of winning matches, we need Andy. He makes a pivotal difference but you've still got to respect his schedule because he's going deep in every slam.
"We'll speak next year and see how it fits in but he's really enjoyed it, he's been a great part of it and he loves Davis Cup. The signs are positive that he wants to play next year.
"There is still a lot of hard work to go and with the level going up, we need more competition for singles places and for senior players to improve their ranking.
"We've got a very good team spirit, everyone wants to play and I think it shows when they go out on court that they genuinely want to be here. But it still doesn't lie where we're at with singles, it's not good enough."
Sunday's two singles will be dead rubbers but, with another big crowd expected, Smith said it is very likely Murray will play.