MONTREAL - Ignacio Piatti and Victor Cabrera scored in the first half and the Montreal Impact posted a 2-0 victory over Alajuelense in the first leg of their CONCACAF Champions League semifinal on Wednesday night.

The Impact will take a two-goal lead into the second leg of the two games, aggregate goals series on April 7 in Alajuela, Costa Rica.

Buoyed by at-times deafening sound from the crowd of 33,675 at the domed Olympic Stadium, the Impact took the initiative from the kickoff and were up two goals in the opening 14 minutes.

A Dominic Odura pass was backheeled by rookie Cameron Porter to Piatti on the left side for a blast that went in off a post only 10 minutes in.

Four minutes later, a Marco Donadel corner kick was played into the middle by Bakary Soumare for Cabrera to slot home.

Alajuelense's best chance came from a 22-yard free kick by Jose Ortiz that was cleared by Donny Toia.