MADRID, Sept 8 (Reuters) - Jordi Alba has quickly filled the boots of 2010 World Cup winner Joan Capdevila since taking over the left back spot for Spain in late 2011 but with one key difference: he can't stop scoring.

The diminutive but speedy 24-year-old, who buried a memorable effort past Gianluigi Buffon for the world and European champions in their 4-0 drubbing of Italy in the Euro 2012 final, has netted two of Spain's 10 goals in qualifying matches for next year's World Cup finals in Brazil.

Alba also struck twice against Nigeria at the Confederations Cup in June and while efficiently performing his defensive duties he regularly wreaks havoc down the wing with his perfectly timed dashes into space.

The Barcelona fullback's goal against Finland on Friday, when he raced onto a chipped Cesc Fabregas pass and finished like a centre forward, set Spain on their way to a 2-0 win that stretched their lead over France at the top of Group I to three points with two games left.

Catalonia-born Alba spent seven years in Barcelona's academy before joining Valencia and then returning to the Nou Camp at the end of the 2011-12 season.

His performances for club and country have earned him warm praise from fellow left backs, including Capdevila, now 35 and playing for Barca's La Liga rivals Espanyol, and former Brazil and Real Madrid great Roberto Carlos.

"How could he not eclipse my achievements?" Capdevila, who scored four goals in 60 appearances for his country, was quoted as saying in Marca sports daily on Sunday.

"Jordi is an ace, a phenomenon," he added.

 
"He is a modern fullback, mobile, very fast and blessed with excellent offensive nous.

"Add to that the fact that with each match he is getting better at defending. He is on his way to becoming the best in the world and it won't take him long to get there."

Alba takes such acclaim in his stride and noted this week that his eye for goal is the result of time spent playing as a forward in his formative years.

"I have had the good fortune to play for Barcelona and the Spanish national team, whose style of play are brilliantly suited to mine," he told a news conference on Sunday ahead of Tuesday's friendly against Chile in Geneva.

"The style of play we develop at Barca and with Spain allows me to attack and score more goals," he added.

"I played up front all my life and some of that has stuck. I hope to be among the best by the time I finish my career."

Carlos told Marca that, along with Real's Brazil left back Marcelo, Alba was the best in his position.

"The explosiveness he possesses make him just as important in defence and attack," Carlos said. "And he has the gift of scoring goals."

Spain will need Alba to be firing on all cylinders if they are to defend their world title in Brazil next year. Their final two qualifying matches are at home to Belarus and Georgia next month.