World number three Andy Murray steered Britain back among the Davis Cup elite with a straight sets victory over Croatia's Ivan Dodig in Umag on Sunday.
Murray, who turned out for his country for the first time in two years, capped a fine weekend with a 6-4, 6-2, 6-4 victory to give Britain a 3-1 lead and put them in next week's draw for the World Group after a five-year absence.
Spain secured their place in the Davis Cup's elite World Group when Rafael Nadal teamed up with Marc Lopez to beat Sergiy Stakhovsky and Denis Molchanov of Ukraine 6-2, 6-7, 6-3, 6-4 in their playoff on Saturday.
Victory for the Spanish pair on the red clay at the Magic Box arena gave them an unassailable 3-0 lead in the best-of-five tie following Friday's singles wins for Nadal and Fernando Verdasco.
Switzerland and the Netherlands beat Ecuador and Austria respectively in their playoffs.
Results: World Group play-offs: At Madrid: Spain lead Ukraine 3-0 (On Saturday: Marc Lopez/ Rafael Nadal bt Denys Molchanov/ Serhiy Stakhovsky 6-2, 6-7 (6-8), 6-3, 6-4).
At Groningen: Netherlands lead Austria 3-0 (On Saturday: Robin Haase/ Jean Julien Rojer bt Oliver Marach/ Julian Knowle 4-6, 6-3, 6-4, 7-5).
At Umag: Croatia trail Great Britain 1-3 (On Sunday: Ivan Dogic lt to Andy Murray 4-6, 2-6, 4-6; On Saturday: Dogic/ Mate Pavic lt to Colin Fleming/ Murray 3-6, 2-6, 7-6 (8-6), 1-6).
At Neuchatel: Switzerland lead Ecuador 3-0 (On Saturday: Michael Lammer/ Stanislas Wawrinka bt Emilio Gomez/ Roberto Quiroz 6-3, 6-4, 3-6, 6-7 (7-9) 6-4).
At Ulm: Germany lead Brazil 2-1 (On Saturday: Martin Emmrich/ Daniel Brands lt to Marcelo Melo/ Bruno Soares 3-6, 4-6, 4-6).
At Warsaw: Poland trail Australia (On Saturday: Mariusz Fyrstenberg/ Marcin Matkowski bt Chris Guccione/ Nick Kyrgios 5-7, 6-4, 6-2, 6-7, (5-7), 6-4).
At Antwerp: Belgium trail Israel 1-2 (On Saturday: Steve Darcis/ Olivier Rochus lt to Jonathan Erlich/ Andy Ram 3-6, 7-5, 6-1, 5-7, 3-6).
At Tokyo: Japan bt Columbia 3-2 (On Sunday: Go Saeda bt Alejandro Falla 4-6, 6-4, 6-3, 6-3; Kei Nishikori bt Santiago Giraldo 6-1, 6-2, 6-4; On Saturday: Tatsumo Ito/ Yuichi Sugita lt to Juan-Sebastian Cabal/ Robert Farah 1-6, 2-6, 1-6).