* Defending champions in third final in five years
* Czechs will face either Canada or Serbia (Adds Argentina quotes and details)
By Jason Hovet
PRAGUE, Sept 14 (Reuters) - Tomas Berdych and Radek Stepanek put defending champions Czech Republic into the Davis Cup final by beating Argentina's Carlos Berlocq and Horacio Zeballos in the doubles on Saturday.
World number five Berdych and U.S. Open doubles champion Stepanek defeated the Argentines 6-3 6-4 6-2, giving the Czechs an unassailable 3-0 lead in their semi-final and a place in their third final in five years.
They will face either Canada or Serbia on Nov. 15-17.
The Czechs' all-time best doubles pairing with a 13-1 record were playing together for the first time this season and in front of a crowd of more than 11,000 at Prague's O2 Arena, where the team lifted the trophy for the first time as an independent nation last year.
Stepanek, coming into the competition on the back of winning the men's doubles title with Leander Paes at Flushing Meadows last weekend, immediately set his sights on another Davis Cup title.
"We would like to keep that trophy because it's beautiful," he said at the courtside after the match.
"It feels great; this competition means a lot to us. It is an honour to play in front of our home crowd, our home fans."
The Czech duo, who played in every live rubber in the title run last year, teamed up for the first time this year after injuries prevented them playing the early rounds together.
With the crowd behind them, they looked more at ease with the fast pace on the hard court surface, which gave Argentina problems just as it did Spain in last year's final.
Argentina went into the tie as underdogs and played without world number seven Juan Martin Del Potro, who sat out this year's competition, and their best doubles player, David Nalbandian, who underwent shoulder surgery in May.
Captain Martin Jaite made no excuses, however. "We played against a great team...one of the best teams at the moment in the Davis Cup," he said.
The Czech pair, following up singles wins over Juan Monaco and Leonardo Mayer on Friday, showed their experience in the first set on Saturday, fighting off a break point to go up 4-3. They then broke the Argentines before serving out the set.
The second set played out similarly before the Czechs were able to break Berlocq's serve for the second time to go up 4-3. The Argentine pair got back to 5-4 but Berdych served well and finished off the set with a smash.
Berdych, the Czechs' top player, broke Zeballos in the third set to go up 3-2 when he fired a forehand winner from the baseline that made Berlocq step out of the way.
The Czechs never looked back and Berdych sent the team through to the final on his first match ball.
"We played a great game," Berdych said. "Everything was in the right place today. We didn't drop a serve. We were taking our chances."
The Czech Republic also defeated Argentina in Buenos Aires in last year's semi-finals on their way to lifting the Cup for the first time since Czechoslovakia won it in 1980.
"It was a tough day. We didn't have too many chances," Zeballos, who had won his previous two Davis Cup doubles matches paired with Nalbandian, said.
"But for sure tomorrow when I wake up I will say, okay, we lost in the semi-finals. So it is a very good year for our country." (Editing by Clare Fallon)