HIGHLIGHTS + REPORT: Valencia v Barcelona

Barcelona boss Luis Enrique has confirmed that Andres Iniesta is likely to miss a number of weeks as a result of a knee injury sustained against Valencia.

The Spain international was carried off on a stretcher in obvious pain after a challenge from Enzo Perez during the first half of Barca's 3-2 LaLiga win at Mestalla on Sunday (AEDT).

The club later confirmed he had sustained damage to the lateral collateral ligament of his right knee, with initial reports in his homeland suggesting he will not play again until 2017.

Iniesta sent a tweet some time later to thank fans for the messages of support.

"It is not an easy time. There will be a few weeks out, but it could have been much worse. I wanted to thank you for the messages of encouragement! Hugs!" he wrote on his official Twitter account.

Luis Enrique says further tests will be carried out on Monday (AEDT), but admitted that the problem looked "serious", while he questioned how Perez escaped without even a yellow card.

"It was a game where a huge amount happened," he said. "The worst thing was the injury to Andres in an incident that everyone on the bench could see very clearly.

"I explained perfectly earlier. It's a clear incident in which we saw the player get injured, and there was no yellow card. Tomorrow we'll see the severity of the injury but, yes, it'll be weeks. It's a serious one," he added.

The visitors snatched the win through Lionel Messi's 94th-minute penalty — his second goal of the match. Luis Suarez had levelled matters at 2-2 after two goals in quick succession from Barca loanee Munir El Haddadi and Rodrigo.

Luis Enrique hailed his side's determination to fight for the win after it surrendered its advantage in a "crazy" start to the second half.

"The game had various phases. We started very well, we were able to create some superiority at 1-0 but then they drew level," he said.

"At the start of the second half, we had a crazy five minutes. We were lucky to get back to 2-2. We lost some control with our desire to win but in the end the team showed the desire to overcome adversity.

"It was a Valencia-Barca in keeping with the tradition of this game."

Luis Enrique admitted he was surprised to see Messi drill his penalty low to the right of goalkeeper Diego Alves, who holds the record for spot-kick saves in LaLiga, with 19 from 37 faced.

"He created some doubt last season and against him is Alves, who seems huge when he's in goal," he said.

"I thought he would shoot to the other side, others said he would go down the middle, and in the end he chose the side he wanted. He assumed the responsibility and it's a glorious feeling."