MAR DEL PLATA, Argentina -- Who needs Rafael Nadal?
Verdasco outlasted Acasuso 6-3, 6-7 (3), 4-6, 6-3, 6-1 before a boisterous Argentine crowd at Islas Malvinas Stadium. The fans went quiet as Argentina lost at home for the first time in 10 years in Davis Cup competition.
"It's the most exciting victory of my life," Verdasco said. "Playing for my country, against the best players, it's a dream."
Verdasco, replacing David Ferrer in the reverse singles, overcame nine double-faults to beat a shaky Acasuso in 3 hours, 56 minutes. The 48th-ranked Acasuso was a late replacement for the injured Juan Martin del Potro, Argentina's top-ranked player at No. 9.
Argentina entered the heavy favorite after Nadal withdrew last week because of a knee injury.
"Nadal gave us several victories, and thanks to him we are here," Spain captain Emilio Sanchez Vicario said. "But the players who are here are the ones who deserve all the credit now."
After winning match point, Verdasco dropped to the ground in celebration and was embraced by his teammates. Argentina entered the heavy favorite after Nadal withdrew last week because of a knee injury.
"Spectacular," Nadal said on Spanish state television. "Sincerely, this is history."
Nadal said he would've loved to have been in Argentina to celebrate with his teammates.
"Moments like these, sharing them with your teammates are unforgettable," Nadal said. "They played a tremendous tie -- it's time for them to enjoy it."
Despite the support of nearly 10,000 fans, Acasuso was not able to keep up with Verdasco, who played well in the doubles win alongside Feliciano Lopez on Saturday. Acasuso served 14 aces, but had 47 unforced errors.
Both players struggled on serve, with Verdasco broken five times and Acasuso on nine occasions.
Verdasco broke Acasuso's service in the sixth game, going up 4-2 to easily win the first set.
That silenced the crowd, but Acasuso lifted the fans by winning the second-set tiebreaker after each player broke twice. One of the breaks came when Acasuso was serving for the set at 5-4.
The Argentine kept pressing in the third set, breaking Verdasco in the first game and twice more. Verdasco stayed in the match with a solid fourth set, breaking Acasuso to lead 4-2 and winning four of the last five games.
The Spaniard dominated the fifth set, winning the first four games and cruising to victory. Argentina last lost at home during Davis Cup competition in 1998 to Slovakia.
Argentina had reached the final twice, losing to the U.S. in 1981 and Russia in 2006.
Acasuso had won his only other match against Verdasco, whose Davis Cup singles record improved to 4-3. Acasuso is 5-3.
The 20-year-old Del Potro, one of the hottest players on tour this year, injured his right thigh in a four-set loss to Lopez on Friday. Verdasco came in for Ferrer after he lost his singles match in three sets to David Nalbandian on Friday.
Spain's doubles win Saturday ensured it needed just one victory on the final day to clinch the title, while the Argentines were left with the difficult task of having to win both matches.
The title moved Spain from fourth to second in Davis Cup rankings, behind Russia. Argentina would have reached No. 1 with a victory.
The United States won last year's final, beating Russia.