Luckily for Barcelona, the 2-2 draw and two points dropped was not punished as Atletico Madrid lost 1-0 at Real Betis on Sunday.
The hosts were 2-0 down after 32 minutes after a counter-attack goal from Kevin Gameiro and Dani Parejo's spot-kick.
Arturo Vidal flicked the ball to Messi, who took one touch to set himself up before unleashing an effort beyond Neto in the Valencia goal.
Madrid-based Getafe are up to fifth after a goalless draw at Levante, which was marred by 11 visiting fans being arrested for provoking a clash with rival supporters outside the stadium in Valencia.
"Speaking after the game, Barça boss Ernesto Valverde said: "(Messi) has a small problem.
'We will have to wait to see what medical staff say.
Lionel Messi rescued a point for Barcelona by bagging a brace and he did it in typically stunning, stunning fashion.
Barcelona's winning streak in la Liga ended at eight matches in a row.
It was Messi's 20th league goal of the season and the ninth consecutive match in which he's found the net, across all competitions.
Jordi Alba replaced Nelson Semedo at the break as Barcelona upped their game at the start of the second stanza.
Camp Nou was silenced once again in the 31st minute, however, when Roberto conceded a penalty for bundling into the back of Wass.
And in the 65th minute Barcelona level the scores after Messi's wonderful strike from the edge of the box rested in the bottom corner of Valencia. "If he's in good shape, he'll play on Wednesday [against Madrid]".
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.
Real Sociedad won the Basque derby 2-1 at home to Athletic Bilbao to move to eighth in the table.