Carlos Ochoa scored the equalizer as Chiapas drew 1-1 at home against Santos in the first leg of the Mexican football league playoffs on Thursday.
Pachuca-Monterrey also finished 1-1 in the other playoff quarterfinal played earlier in the day.
Chiapas striker Ochoa scored at the back post in the 34th minute to cancel out Fernando Arce's 22nd-minute opener for Santos. Chiapas finished the match with 10 men.
The results mean Monterrey and Santos only need to draw at home in the return legs on Saturday to progress to the semifinals, because both clubs finished higher in the regular season standings than their rivals.
America drew 0-0 at San Luis and Cruz Azul won 2-1 at UNAM Pumas on Wednesday in the other playoff quarterfinals.
The return legs of the America-San Luis and Cruz Azul-Pumas matches are scheduled for Saturday.
In Chiapas, Santos striker Daniel Luduena broke through the middle and offloaded the ball into the right channel for Arce to arrive late and shoot past Jaguares keeper Jorge Villalpando at the near post to open the scoring.
Ochoa, a former Santos player, equalized when he controlled a deep Alan Zamora cross and lifted the ball across keeper Oswaldo Sanchez.
Chiapas had defender Ismael Fuentes sent off with just over ten minutes to play after a late challenge on Rodrigo Ruiz earned his second yellow card.
Santos, which finished third in the regular season league table, will progress to the semifinal if it avoids defeat against Chiapas in the return leg at the Estadio Corona on Sunday.
Monterrey, which finished second behind Cruz Azul in the general standings, has a similar advantage after drawing at Pachuca.
Monterrey forward Neri Cardozo wasted two chances when clean through on Pachuca keeper Miguel Calero in the first half, but laid on the opener with a corner that bounced through to the back post for Jose Maria Basanta to dive in and head home in the 56th minute.
Franco Arizala pulled Pachuca level after cutting inside Basanta in the box and unleashing a left-footed shot that curled into the top corner in the 68th.
Monterrey lost to Pachuca at the same stage of the playoffs last season.
