Clint Dempsey went to England to prove himself.

Being an All-Star starter in Major League Soccer is one thing. Holding a job in the Premier League is quite another.

"You're challenged every day in training, and you know your head is always on the chopping block, and you've got to perform or you're being replaced," he said. "I think being around that environment forces you to take your game to the next level, and I think I have."

Following the retirement of Brian McBride from the U.S. national team, Dempsey has become a key forward for the Americans, who played a World Cup qualifier at Costa Rica on Wednesday night. The 26-year-old Texan was the only U.S. player to score at the 2006 World Cup, and by the following January MLS had sold him to Fulham in an agreement that could be worth up to $4 million.

Once he got to Craven Cottage, it took time to win acceptance €" even on a team that had five U.S. players during the 2007-08 season and became known as "Fulhamerica." He made his debut on Jan. 20, 2007, just 10 days after receiving his British work permit, and beat Robbie Keane to a loose ball two minutes after coming on, a play that created a penalty kick in a 1-1 tie against Tottenham. He got his first goal in his 11th game, beating Liverpool 1-0 and helping ensure Fulham remained in the Premier League.

Dempsey scored six goals, all in the league, the following season, and had eight this season, including a 77th-minute equalizer against Swansea as Fulham advanced to the quarterfinals of the FA Cup. He also scored twice as the Cottagers shocked Chelsea 2-2 and twice in a 3-1 win at Manchester City.

In a league where some players wear long sleeves and gloves, he prefers short sleeves, saying the cold isn't nearly as tough as it was with the New England Revolution. Then again, Dempsey's shown before he has a style all his own €" he even recorded a rap song as part of a marketing promotion before the 2006 Cup.

"He's gone from strength to strength, I would say," Fulham coach Roy Hodgson said after watching Dempsey run hard for 87 minutes in a 0-0 tie at Arsenal. "At the start of the season, to be fair, not through any real fault of his own, I left him out of the team ... but that wasn't because he was bad, it was just a tactical choice on my part.

"But since he's got back into the team. ... He's really been quite fantastic, and, you know, he works so hard. He's a constant menace offensively."

Dempsey has 13 goals in 49 appearances with the U.S. national team, including four in an important four-match span in World Cup qualifying last year. He put the U.S. ahead just 53 seconds in and added another as the Americans opened with an 8-0 rout of Barbados, got the lone goal as the U.S. won its first game at Cuba since 1947, then scored in a 3-0 victory over Trinidad and Tobago.

"He's one of a number of guys that after 2006 I think we challenged to take bigger roles, to take responsibility, to see the picture of what the team is all about and not just be thinking about what's good for them, so yes, I do think his role has grown," U.S. coach Bob Bradley said.

By the time the U.S. team gets to South Africa for next year's World Cup, Dempsey will be counted on to be a leader along with Landon Donovan, DaMarcus Beasley, Carlos Bocanegra and goalkeeper Tim Howard. Lean and fast, Dempsey can spurt through a defense in a manner that perhaps only Donovan and maybe Jozy Altidore can match among the current crop of Americans.

He likes to be counted upon, thinking of himself as "a player that's a fighter for you, that will put everything on line." He thinks going to Fulham hastened his development.

"I think I've become more of a complete player," Dempsey said. "I think a weakness before I went over there was my defense, and I think that I've shown that, you know, now that that's a strength of mine. And I think the speed of play in which I play, being able to see passes early, I think that's improved being over there.

"I think if I had stayed in MLS, I think you can get, you know, complacent. There's not too many people challenging for spots. You don't have a lot of depth on teams. You always kind of felt you were going to start, and you felt like you weren't being pushed week in and week out."