Argentinian international midfielder Javier Mascherano completed his 17.25 million pound ($26.6 million) transfer to Spanish La Liga champion Barcelona from English Premier League giant Liverpool on Monday.

The 26-year-old - who captained Argentina at the World Cup finals, where it was humbled 4-0 in the quarter-finals by Germany - signed a four-year contract after passing a five-hour medical, according to the purchasing club's website.

The get-out clause in the midfielder's contract is 90 million euros ($113.9 million).

Mascherano said that he was not going to the Spanish club "for a holiday but to take advantage of a once in a lifetime opportunity" to play for a team that was made up of world champions.

Mascherano paid tribute to the caliber of his new teammates and said he was determined to earn his place in the squad.

"There are great players in my position," he said.

"I would be stupid if I thought that I was coming here to play everything. You have to respect the people who are doing well and who have won everything.

"In the positions in which I can play, there are three world champions," he said in reference to Sergio Busquets, Xavi Hernandez and Andres Iniesta.

"The day I'm called on to play, I want to do it in the best possible way and will do everything to ensure the absence of the teammate who had to come off isn't felt."

He said: "I'm coming to a team which has in the past few years won everything. It is made up of world champions. I will try to help the team continue winning things.

"In the future, I am certain to say that I was a better player for having played in this club."