Madrid, Nov 12 (IANS): FC Barcelona coach Tata Martino and midfielder Cesc Fabregas have expressed concern over the muscle problems affecting striker Lionel Messi.

Messi was forced out of his side's 4-1 win away to Betis Sunday night with an injury to his left hamstring. It is the latest in a series of muscle injuries which have affected the Argentine since the run in to the end of last season and it happened in his fifth match back after overcoming a similar injury, reports Xinhua.

The setback means he will not play in Argentina's forthcoming friendly matches against Ecuador and Bosnia-Herzegovina, and is doubtful for the next two weeks of Spanish Primera Liga action.

"We are going to have to talk to Leo about whether or not he is worried, but it is the third injury that he has suffered of this kind (this season) and we don't know how it has affected his confidence," said Martino.

"I can't explain what is happening to him and I don't know whether or not it is down to coincidence, but I don't want to speak about things I don't know. First of all I want to know how serious the injury is and then get him fit again."

"We have the best player in the world but after that we have another four who are in the top six or seven in the world," said the Barcelona coach.

Cesc Fabregas was one of Barca's heroes in the win with two goals and speaking after the game, the midfielder who has suffered his share of injuries, had a word of advice for Messi.

"He needs to rest for the time that is needed. He needs to be able to use his explosive pace in order to shine. Something similar happened to me and it is very difficult, you think that you have recovered but it's not the case," said Cesc, who insisted that patience is important with this kind of muscle problem.