Gerardo Martino has completed his deal to coach Barcelona for the next two seasons.Barcelona announced on Tuesday that the Argentine coach would take over from Tito Vilanova, who stepped down last week to proceed with a cancer treatment that was "incompatible" with his coaching duties.The 50-year-old Martino will be officially presented later on Friday.Martino has never coached in Europe, but led Newell's Old Boys to the Argentine league title last season and Paraguay to the quarterfinals of the World Cup for the first time in 2010.He has already received the backing of Barcelona star and countryman Lionel Messi."He (is) a great coach and his record speaks for itself. He showed he could do things well both at Newell's and with Paraguay," Messi said. "I am convinced he will do well at Barca."Martino must quickly take charge of his new team with the Spanish league set to begin on August 17-18.And he will have a tough act to follow.Vilanova led Barcelona to the Spanish league title last season and helped former coach Pep Guardiola guide Barcelona to an unprecedented 14 of a possible 19 titles as his assistant from 2008-12.In his favor, Martino will receive a star-studded squad with Messi, several Spanish internationals such as Andres Iniesta, Xavi Hernandez, and Cesc Fabregas, and the club's latest major signing, Brazil striker Neymar.But his chances for success may largely depend on how well he can convince this diverse collection of players used to winning, and winning in the Barcelona way of attacking football, that he is the right man to carry the team through this unexpected transition.Messi played for Newell's in his home town of Rosario as a young boy before his move to Spain to join Barcelona's "La Masia" training academy. The four-time world player of the year has been Martino's most vocal supporter so far, even though they don't know each other personally."The truth is that I don't know how he works, I have never sat down and spoken to him face to face. But from what I have seen and from what I have been told I am convinced that he will do well at Barca," said Messi. "That's what we all want. (Sports director Andoni) Zubizarreta and the club chose him, but I am convinced that he is coming because he has proven that is a great coach."