America all but secured their spot in the CONCACAF Champions League quarter-finals, while Dallas were edged on Wednesday.
Record seven-time winners America crushed Deportivo Saprissa 5-1 in San Jose in the first leg of their last-16 tie.
The Mexican giants took control of the tie in the first half as Cecilio Dominguez scored a brace and Mateus Uribe also struck.
Dominguez placed in the opener in the second minute before Miguel Herrera's men doubled their lead, Oribe Peralta setting up Uribe.
It was 3-0 prior to the break as Dominguez scored again, with Renato Ibarra squeezing in another finish for America in the 59th minute.
While Ariel Rodriguez got the hosts on the board, Uribe struck again to see America in complete control of the tie.
In Panama, Tauro edged Dallas 1-0 in their first leg.
Edwin Aguilar headed in the only goal of the game in the 57th minute to see Tauro to a hard-fought victory.
In the day's other game, Tijuana edged Motagua and 1-0.
The clash, being played at H-E-B Park in Texas due to the "political and social situation" in Honduras, was suspended during the second half because of a storm, before players returned to complete the match.
And Tijuana emerged victors thanks to Ignacio Rivero's 71st-minute strike.