Lionel Messi scored either side of half-time to help Barcelona overturn a two-goal deficit and earn a 2-2 draw with Valencia at the Camp Nou on Saturday.
Valencia struck twice in eight first-half minutes, first through Kevin Gameiro and then via Dani Parejo's penalty, following a foul by Sergi Roberto.
But a foul by Toni Lato led to Messi halving the hosts' deficit six minutes before the interval with a spot kick of his own as the teams went to the dressing room with Valencia leading 2-1.
Messi then struck again in the 64th minute, curling in a shot from 20 yards after Arturo Vidal had laid the ball off to him at the top of the penalty area to bring Barca level at 2-2.
Neither team could find a winner in the remaining 30 minutes of the match, but the draw ensured Barca avoided a first league loss since November and took them to 50 points from 22 games.
However, the dropped points leaves the door open for Atletico Madrid to close the gap on the La Liga leaders, who they trail by six ahead of their match with Real Betis on Sunday.
Both teams had enjoyed remarkable comebacks during the week to reach the Copa del Rey semifinals, with Barca thrashing Sevilla 6-1 to win 8-3 on aggregate and Valencia seeing off Getafe 3-1 for a 3-2 aggregate win with two goals in stoppage time.
Valverde, who had warned of the dangers of exhaustion at this stage of the season, started without Jordi Alba and was missing Sergio Busquets through suspension and Ousmane Dembele through injury.
Valencia, who began the season in the Champions League but have had a haphazard campaign and are seventh in the standings, looked to be on their way to a third league win in six visits to the Nou Camp after making a flying start.
Marcelino's side's strategy of intense pressing and rapid counter-attacks paid off with their two goals while their organisation and discipline prevented Barca from hitting top gear, even through Sergi Roberto almost equalised before the interval when his shot hit the post.
Valverde threw on Alba at the start of the second half and his side immediately looked more dangerous yet once again their fate rested on the brilliance of their all-time top scorer Messi, who struck his 21st league goal of the season to level the game.
There was consternation inside the Nou Camp when the Argentine required treatment on the sidelines soon after his second goal although there was tangible relief when he was able to continue, even though he could not summon up a winner.
Information from Reuters was used in this report.