CHARLESTON, South Carolina, Sept 26 (Reuters) - World number two Andy Roddick says the United States will probably be the underdogs in the Davis Cup final against hosts Spain in December.

The U.S. clinched their place in the final with a 4-0 win over Belarus here on Sunday while Spain went through for the third time in five years thanks to a 4-1 victory over France in Alicante.

The U.S. and Spain have met six times in the Davis Cup, with the Americans 4-2 up. Both Spanish wins have been at home on clay, the likely surface for the December 3-5 final.

Spain triumphed in the 2000 semis and in the third round in 1965 but also lost to the U.S. at home on clay in 1972.

"On paper, if you look at (all) clay-court results, we're probably the underdogs," Roddick told reporters after winning his two singles matches against Belarus.

"But I definitely think we can give ourselves a chance to win.

"It's definitely on my list of...big goals," the hard-serving Roddick said. "And to kind of know we're nine sets away from doing that, it feels pretty good."

Clay might not be his "most comfortable surface," Roddick said, "but I'm not going to let it psyche me out. I'm going to go over there, I'm going to give it my all."

After all, he said, it is time to erase the stigma of never having played in a Davis Cup final.

The U.S. have not been in the final since 1997, and have not won the title since 1995.

ULTIMATE GOAL

Getting to the final is another great honour for the close-knit American team, said captain Patrick McEnroe.

"It's the ultimate to go to Spain," he said. "They (Spain) have got, if not the best team, certainly one of the best in the world, particularly at home on clay."

McEnroe is likely to challenge the Spaniards with the same team that dropped only one set against Belarus, Roddick, Olympic silver medallist Mardy Fish and twins Bob and Mike Bryan in the doubles.

Roddick is the obvious choice for the top singles spot, and McEnroe appears to have found his number two in Fish, who beat Belarus number one Max Mirnyi on Friday after several pundits had questioned his selection in the team.

"I'm never going to stay locked in completely but certainly Mardy continues to come along," McEnroe said. "This was a big win for him here."

Roddick also offered Fish a vote of confidence.

"On clay, I think Mardy is probably the clear choice," Roddick said. "He has won on clay for us before, away, and he won a huge match (on Friday), so I feel like he has the experience."

There is a bit of history on the side of the U.S. The last time they won the Davis Cup it was on clay, in Moscow nine years ago.