Tigres UANL were held to a 1-1 draw at home to Pachuca in the first leg of their CONCACAF Champions League final.
Raul Lopez put visitors Pachuca ahead away from home at the Estadio Universitario de Nuevo Leon on Tuesday.
But an Ismael Sosa goal brought Tigres - last season's runners-up - level before Eduardo Vargas missed a second-half penalty for the hosts in the all-Mexican decider.
Pachuca were fortunate to take a third-minute lead.
A Lopez free-kick from 35 yards took a huge deflection off the wall, wrong-footing goalkeeper Nahuel Guzman and finding the bottom corner.
Ricardo Ferretti's hosts were level just after the half-hour mark thanks to an Alfonso Blanco error.
The keeper spilled a Jesus Duenas cross and Sosa made the most of it, putting away the chance to make it 1-1.
Tigres had a glorious chance to take the lead in the 67th minute, but Vargas was denied by a diving Blanco from the penalty spot.
The second leg will be played at Pachuca on April 26.