Tigres began in disastrous fashion as they fell behind to Carlos Quintero's strike within a minute of kick-off.
Juninho levelled after 36 minutes, though, and that was enough to keep his side at the summit as second-placed Club America were also held, 2-2 by Toluca.
America were agonisingly close to victory as they led 2-1 when Raul Jimenez (34) and Osvaldo Martinez (82 pen) responded to Diego Novaretti's 18th-minute opener.
But Carlos Rodriguez struck in the dying seconds to rescue a point for Toluca and deny America top spot.
Atlas pulled level on points with America as they came from behind to beat Monterrey 2-1.
Omar Riveron put Monterrey ahead in the seventh minute, but goals either side of half-time from Jose Luis Chavez (36) and Omar Bravo (54) turned the match around.
Goals from Angel Reyna (3) and Christian Suarez (77) gave Pachuca a 2-1 win over Cruz Azul, who responded through Teofilo Gutierrez's 34th-minute penalty.
Edwin Hernandez (13) and Yovanny Arrechea (63) scored to give Leon their first win of the Clausura, 2-0 over San Luis, leaving their opponents the only side without a victory.