Miguel Herrera's side are winless since October, without a victory in their past five and having drawn four straight.
But two away goals at Tigres UANL was enough to edge through their quarter-final, which was expected after they finished top of the Apertura in the regular season.
America, who are away from home for the first leg on Thursday, have failed to beat Toluca in 2013 with their two meetings finishing in draws.
Herrera has been awarded the full-time job in charge of Mexico after leading his country to the 2014 FIFA World Cup with a play-off win over New Zealand.
With his future sorted – he takes over full-time at the end of the season – perhaps his America side can return to the form they showed earlier in the campaign.
America have several outlets from which they can find their goals, with Raul Jimenez leading the way with nine this season.
Rubens Sambueza and Narciso Mina are also capable of finding the net and Herrera will be hoping they can lead his side to the final.
The second leg of the tie will be played on Sunday.
In the other semi-final, Santos Laguna face Leon in what should be two close encounters.
Both claimed impressive wins in their last-eight ties, with Santos Laguna beating Queretaro 6-3 and Leon hammering Morelia 7-3.
In their two matches this year, both resulted in 2-0 wins – first to Santos Laguna and secondly to Leon away from home.
Oribe Peralta (Santos Laguna) and Mauro Boselli (Leon) could make the difference, with both scoring regularly this season.
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