Lionel Messi had a penalty saved as Barcelona drew 1-1 at Valencia in the first leg of their Copa del Rey semi-final at the Mestalla.
The Argentinian wasted the chance to put the visitors in front after Carlos Puyol had cancelled out Jonas' opener for the hosts.
The visitors rode their luck in the first half, though, and might have had goalkeeper Jose Manuel Pinto sent off inside 20 minutes when a clear handball outside the area went unspotted by the officials.
Barca went into the game on the back of a goalless draw with Villarreal which dropped them seven points behind Real Madrid in the race for the Primera Division title, and struggled early on against Valencia.
They had a let-off when Pinto rushed off his line to close down Roberto Soldado and was out of his area when he stopped the ball with his arm as the striker looked to poke it past him.
The offence went unpunished, though, and the keeper survived another scare when Soldado volleyed powerfully over from an Ever Banega corner.
Alexis Sanchez stabbed horribly wide when through on goal for Barca, but Valencia were on top and went ahead in the 27th minute when Jeremy Mathieu raced down the left and pulled the ball back for Jonas to sidefoot into the top corner.
But Puyol headed Barcelona level in the 35th minute, moments after Alves had brilliantly turned Sanchez's shot round a post.
The Chilean had a goal ruled out for offside three minutes after the break, going a fraction too early as he looked to run out to a Messi through-ball.
The Argentinian's night was not going any better as he saw his penalty saved in the 56th minute. Thiago Alcantara was clearly tripped in the area, but Messi's weak penalty was a good height for Alves and not close enough to the corner, the keeper diving to his left to push the shot away.
Substitute Dani Alves fired against the far post when he should have scored as the Catalans dominated the second half, but they could not find a winner.