As you were in Mexico after goalless Sunday

MEXICO CITY, Oct 10 (Reuters) - A goalless Sunday left the status quo unchanged in the Mexican Apertura championship with the leaders of the three groups all drawing 0-0 in the three matches played.

Group One leaders Monterrey defended their 11-match unbeaten record away to America at the Azteca while the leaders of the other two groups, title holders Toluca and Cruz Azul played each other and also drew 0-0.

Santos Laguna, second in Group One a point behind Monterrey, drew away to Morelia, who are fourth in Group Three 11 points adrift of Cruz Azul but only two behind second-placed Chiapas with six matches to go in the round-robin phase.

In the first phase the teams all play each other once regardless of their groups. The top two teams in each group plus the next two best placed sides overall then go into the quarter-finals.

There were goals in all five of Saturday's matches with Tigres UANL crushing Estudiantes UAG 5-0 in the northern city of Monterrey which has been plagued by drugs-related violence.

The match was held amid a massive security operation carried out by police and military personnel but a bomb threat turned out to be a hoax.