Tigres dropped their first points of the new Mexican Apertura season after being held to a goalless draw by Atlas.
Tigres, who had won their opening two matches, still moved to the top of the standings with the result though, lying level on seven points with Santos Laguna.
Monterrey picked up their first win after defeating bottom side Jaguares 2-1.
All the goals game in the first half, with efforts from Monterry duo Hector Morales (four) and Neri Cardozo (31) sandwiching a 22nd-minute equaliser from Jaguares' Luis Esqueda.
Pachuca were also celebrating their maiden three-point haul after a 62nd-minute goal from Paulo Da Silva earned them victory at second-bottom Queretaro, who are still searching for their first point and first goal.
Also, the match between Cruz Azul and Guadalajara finished goalless.