Carlos Darwin Quintero scored in the 89th minute at the Estadio Omnilife to see Santos claim a 1-0 win over Guadalajara on Sunday.
The late goal, Quintero's second of the Apertura season, helps Santos preserve its perfect start as the club looks to build upon its Clausura title.
Guadalajara is still searching for its first point of the season, losing its first two matches by a combined score of 3-1.
Santos is tied on six points with UNAM and Toluca after their respective 3-0 and 3-1 wins over Queretaro and Puebla on Sunday.
Also tied for the Apertura lead with six points are Tigres and Leon. Tigres claimed a 2-1 win over Atlante on Saturday while Leon thrashed Tijuana, 4-0, on Friday.
Elsewhere in Mexican Primera Division play on Saturday, Atlas downed Pachuca in a 3-0 win, America topped Jaguares 4-2 and Cruz Azul edged San Luis 2-1.
In addition to Leon's victory, Friday's action saw Morelia squeak past Monterrey with a 1-0 win.