Marcelino Garcia Toral’s side also moved ahead of Barca as the league’s top scorers with 30 goals in their first 11 games as Dani Parejo, Rodrigo and Santi Mina found the net.
“No one will go undefeated through 38 games, but we are going to enjoy the moment,” said Marcelino.
“In the dressing room there is no euphoria, there is realism and constant analysis.
“We know how difficult it will be to keep this up, it’s practically impossible.”
After travelling to Espanyol following the international break, Valencia host Barca at Mestalla on November 26.
Parejo has been one of many players rejuvenated by Marcelino’s arrival at Mestalla after two seasons in the doldrums for Valencia.
The captain’s clever free-kick that skidded underneath the Leganes wall got Valencia off to a perfect start on 14 minutes.
On loan Paris Saint-Germain winger Goncalo Guedes has been Valencia’s star performer in recent weeks and the Portuguese was inches away from his fourth goal of the season when he struck the post early in the second period.
The hosts had to wait until 19 minutes from time to seal the points with a blistering counter-attack that ended with Spanish international Rodrigo heading home Manchester United loanee Andreas Pereira’s cross.
And the team-spirit in this Valencia side was demonstrated when habitual penalty-taker Parejo let Mina take responsibility from the spot eight minutes from time to round off the scoring.
“It was a phenomenal (gesture). They worked it out themselves and I prefer it like that,” added Marcelino.
“It goes to show the atmosphere there is within the group, which is the foundation for us to perform like this.”
By contrast, Atletico Madrid’s struggle for goals continues but Diego Simeone’s men were bailed out by Thomas Partey’s 91st-minute winner in a 1-0 victory at Deportivo la Coruna.
A 1-1 draw at home to Azerbaijani champions Qarabag all but ended Atletico’s Champions League campaign in midweek amidst a run of one win in eight games.
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