MEXICO CITY, Oct 24 (Reuters) - Guadalajara seriously compromised their chances of reaching the Mexican championship knockout phase when they were held 0-0 by America in the "clasico" between the country's two biggest teams on Sunday.
The result left the Chivas in fourth place in Group One with four matches to go. Monterrey lead the group with 29 points followed by Santos Laguna with 22, Tigres UANL on 19 and Guadalajara with 16.
The top two teams in each of the three groups plus the next two best-placed teams qualify for the knockout rounds.
America lost less ground with the draw at the Azteca in Mexico City. They are third in Group Two on 18 points, four adrift of leaders San Luis and two behind Toluca.
America's 18 points puts them level with Pumas UNAM, third in Group Three - at present the two best-placed teams outside the two top in each group.
Guadalajara and America both played to win knowing the three points were crucial but suffered from bad luck and poor finishing.
Cruz Azul lead Group Three with 29 points after their 1-1 draw at Morelia. They are 10 points ahead of second-placed Chiapas.
Title holders Toluca came from a goal down to beat Puebla 2-1 with goals from Brazilian-born former Mexico midfielder Sinha and Chile's Hector Mancilla after Argentine Gabriel Pereyra had put the visitors ahead.
"If we don't do our job it's going to be tough (to qualify), we mustn't hope for others' mistakes. We have to force our own circumstances to get into the knockout phase," said Toluca coach Jose Manuel de la Torre, who will take charge of the Mexico team after this championship.