By Iain Rogers
MADRID, Sept 14 (Reuters) - Spain secured their place in the Davis Cup's elite World Group when Rafa 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.
Ukraine, whose highest-ranked player is number 40 Alexandr Dolgopolov, were clear underdogs against a team featuring world number two Nadal, who thrashed Stakhovsky on Friday four days after winning a second U.S. Open crown in New York.
Stakhovsky and Molchanov battled back impressively to take the second set on Saturday but the latter appeared to be suffering from a left thigh problem from the third set onwards and Nadal and Lopez took full advantage.
They grabbed the crucial break in the seventh game of the fourth set on the Molchanov serve and went on to clinch victory on their first matchpoint when a Stakhovsky service return drifted wide from Nadal's delivery.
"We had the match under control but at the start of the second set I had a bit of a slump," Nadal said in an interview with Spanish television broadcaster Teledeporte.
"But we got the breaks in the third and fourth sets at the right moment and were able to finish the match off," added the 27-year-old.
"We are still in the World Group and I think that a country with so many players in the top 100 deserves it."
Nadal has shown little sign of fatigue on his return to Davis Cup action after beating top-ranked Novak Djokovic at Flushing Meadows to claim his 13th grand slam singles crown.
The Mallorcan, who had only two days to make the switch from hard court to clay, has not played in the competition since helping Spain to victory against Argentina in the 2011 final in Seville, their third triumph in four years and fifth overall.
Spain were in the playoffs after falling to Milos Raonic's Canada in the first round in Vancouver in February when Nadal, who had just returned from a seven-month injury layoff, did not feature.
They last slipped out of the World Group when they lost away to Mexico in September 1995 before returning to the top tier a year later when a team featuring current captain Alex Corretja beat Denmark in Tarragona.
Corretja, a former world number two, praised his team and particularly Nadal's "incredible effort" and said he was hoping to continue in the job for a third year in 2014.
"It's clear that I would be very excited to continue... but I am not the one to decide," he told Teledeporte.
"I think that given Spain's status in the tennis world and in sport in general it would not be right if we were not in the World Group and hopefully we will have a good year next year."
Verdasco and Tommy Robredo would likely line up in Sunday's dead singles rubbers, Corretja said. (Editing by Clare Fallon)