Pumas UNAM went one step closer to an appearance in the CONCACAF Champions League final, claiming a 2-1 win over Cruz Azul in Tuesday's semi-final first leg.

A Juan Dinenno first-half brace ultimately separated the two side in what was an intense and tight contest.

Cruz Azul were denied the lead in the 20th minute after well-worked move, with Uriel Antuna ruled offside for his finish from Ignacio Rivero's deft reverse pass.

Pumas somehow did not break the deadlock after Cruz Azul goalkeeper Sebastian Jurado's charge for a cross, as Luis Abram scrambled to clear Favio Alvarez's shot off the line.

Pumas eventually got off the mark through Dinenno in the 37th minute and in similarly chaotic circumstances, with another Abram clearance off the line deflecting off the post, then onto Dinenno's foot and in.

He doubled the margin for Pumas in a more conventional manner in first-half injury time, reading Alan Mozo's cross best to powerfully head home past Jurado.

Cruz Azul gave themselves a late lifeline in the tie, though, with Christian Tabo's goal in the 83rd minute.