Salcido and Lucas Lobos had the hosts 2-0 ahead at half-time and, although Fernando Cavenaghi replied in the 66th minute, Salcido's second goal wrapped up the win three minutes from time.
Atlas remain a point behind in second, with Rodrigo Millar's 29th-minute goal enough to see off Guadalajara, who had Marques Lugo sent off in the 17th minute.
Third-placed Club America also won, as Christian Benitez's 22nd-minute goal settled their match against Unam Pumas - who had Molina Granados dismissed midway through the second half.
Two goals in a minute from Hector Mancilla enabled Morelia to come from behind and beat Tijuana, who had led at half-time through Daniel Marquez's goal.
And Queretaro also secured a come-from-behind 2-1 win, with second-half goals from Amaury Escoto and Wilberto Cosme seeing off second from bottom San Luis, who had led at half-time thanks to Mario Ortiz's goal.