Barcelona coach Xavi Hernández says the negativity around the team has affected performances after his side came back from a goal down to beat Alavés 2-1 on Sunday at the Olympic Stadium.

Barça had lost two of their last three games prior to Alavés' visit and were whistled off at half-time after Samu Omorodion gave the visitors a surprise lead after just 17 seconds.

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Robert Lewandowski scored twice in the second half to keep Barça within four points of LaLiga leaders Girona, but the win did little to ease the pressure on Xavi's under-performing team.

"We started on the back foot," Xavi said in his post-game news conference. "[Ilkay] Gündogan lost a ball he would not normally lose and there is a transition. We can't allow these mistakes. It is unacceptable.

"We are gifting teams too many things. We have dropped points at Mallorca, Granada... We are giving too much away and it's generating an insecurity among the players that is not good.

"At half-time, I told them to stay calm and that if we played our football, we would come back. The players were more tense than normal because of everything being generated around the team. And it is not fair.

"It is not fair because there have been injuries and players coming back. We have to be self-critical as well, but it's normal that we don't see the players at their best because they don't feel liberated."

After defeat to Real Madrid, a narrow win over Real Sociedad and a loss Shakhtar Donestsk in midweek, Barça have been subjected to intense criticism in the media. Xavi said that has hit the younger players epecially hard.

"Without doubt what the media say affects how the team plays," he added. "The [media] create situations and scenarios that, for me, are not real. And it affects, without any doubt, the team.

"It happened to me as a player and it's happening to my players. There is a negativity which is not good or positive at all.

"Above all, it affects the youngest players. You see [Iñigo] Martínez, Lewandowski, [João] Cancelo and Gundogan, it does not affect them. But we have a lot of youngsters and we have to protect them and give them confidence.

"[The performances] are our fault, of course, but the youngsters feel a tension that a month ago didn't exist. It is a difficult situation that we have to manage, but it's hard, especially after conceding an early goal."

Samu, on loan at Alavés from Atlético Madrid, should have added to his opening goal. He missed three more big chances in the first-half before Barça turned things around after the break.

Lewandowski's brilliant header from a Jules Koundé cross levelled the scores, with the Polish striker then netting the winner from the penalty spot in the 78th minute after substitute Ferran Torres had been fouled.

"I am sad," Alavés coach Luis García said. "The key is the first half. We have to score two or three and not doing so changes the game. I am proud of the team, but we should have had a bigger lead at half.time.

"There is a big difference between the two sets of players and from there, individually, they can beat you. If you are not perfect in every aspect of the game, they beat you."