Monterrey hit back with two late goals to take a 2-1 lead into their CONCACAF Champions League semi-final second leg with LA Galaxy.
Humberto Suazo and Aldo de Nigris netted in the final eight minutes to swing the tie firmly in the Mexican side's favour.
The Galaxy led after 28 minutes when Robbie Keane's cross was nodded back across goal by Mike Magee for AJ DeLaGarza to head home.
Galaxy star Landon Donovan came on in the 63rd minute for his first spell at the Home Depot Center following a three-month sabbatical and flashed a shot immediately wide.
Monterrey made the MLS side pay on 82 minutes when Suazo turned home Cesar Delgado's cross after de Nigris' initial blocked shot.
Then, four minutes into stoppage time, De Nigris latched onto Guillermo Madrigal's flick on to fire the winner inside the far post.