Valencia looked eager to continue their perfect start to the season and they twice took the lead early on with Eric Abidal scoring an own goal and Pablo Hernandez also netting for the hosts.
However, Barca hit back each time with goals from Pedro Rodriguez and Cesc Fabregas to earn a share of the spoils in a contest which both sides will feel they could have won.
Valencia finished the match with 10 men following the late dismissal of Jordi Alba but it was too late for Barca to take advantage and Los Che remain a point clear of Malaga and Real Betis at the summit.
Big-spending Malaga won their third successive game after summer signing Santi Cazorla curled in a free-kick to seal a 1-0 victory over Athletic Bilbao, while Betis can continue the only remaining 100% record when they face Real Zaragoza on Thursday.
Wednesday's draw at the Mestalla means Real Madrid did not lose any ground on two of their main title rivals, although that will not be much consolation for Jose Mourinho's men following their disappointing goalless draw at Racing Santander.
Having lost at Levante at the weekend, Madrid were desperate to get back to winning ways against Racing but they had to settle for a point.
It might have been worse for the nine-time European champions as well with Racing winger Oscar Serrano bringing the best save of the match out of Iker Casillas.
Whereas Real have been unable to find the back of the net in their last two games, their city rivals Atletico have been in fine scoring form - with new signing Radamel Falcao at the centre of their success.
Having failed to score in their opening two league games, Atletico have now netted 10 times in seven days in matches against Celtic, Racing and now against Sporting Gijon, the latter two games finishing 4-0.
Falcao, who cost Atletico an initial 40million euros after joining from Porto this summer, has scored six of those goals, following up his hat-trick at the weekend with two more this evening.
The Colombian was heavily involved in Atletico's first goal against Sporting as his shot was turned into his own net by Alberto Lora, while Alvaro Dominguez was the other name on the scoresheet.
Wednesday's other La Liga match saw Levante follow up their win over Real Madrid with a 2-1 triumph at Rayo Vallecano.
Goals from Valmiro Valdo and Sergio Ballesteros put Levante 2-0 up and, although Raul Tamudo pulled a goal back in the 72nd minute, Rayo could not force an equaliser after losing Botelho to a red card 13 minutes from time.