Jose Cardozo's men took the upper hand in their two-legged semi-final tie with their Costa Rican opponents, when they claimed a 1-0 road win in April.
Paulo da Silva scored the all-important away goal for Toluca, putting the chances of an all-Liga MX final one step closer to fruition with the second semi-final between Mexican outfits Tijuana and Cruz Azul.
Alajuelense have some history in their favour heading to Toluca's Estadio Nemesio Diaz, as the club won their only visit there 1-0 in the same competition in September 1999.
The same result would force the tie into extra-time, in which the away goals rule would become redundant.
Alajuelense are hopeful of turning the tie around, with goalkeeper Alfonso Quesada claiming his side created plenty of chances in the first leg and just needed to be more clinical in front of goal.
"The team continues to be motivated. The only thing lacking (in the first leg) was a goal. We know that we had chances. They didn't fall, but we haven't lost hope," Quesada said.
"We have objectives and we want to fulfil them and that can be done. We know that we have the confidence to be able to get a result there."
Alajuelense striker Jonathan McDonald missed a penalty at the Estadio Alejandro Morera Soto, but the front man said he had put the miss behind him.
"I have the mental fortitude, it is one of my qualities," McDonald said.
"I have my mind already set on the next match. I take responsibility. I took the ball and I missed the penalty.
"Now to keep the head up and get past this bitter pill."
There is only one goal between Tijuana and Cruz Azul heading to the second leg at the Estadio Azul.
Tijuana lead the leg courtesy of Cristian Pellerano's late penalty for the first-leg hosts, although Cruz Azul are confident of arresting their deficit, with coach Luis Fernando Tena bullish about their chances.
"Our team played a good game (in the first leg). In a week we will make it to the final. We will turn it around," Tena said.
"It will be a very interesting match next week."
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