Matteo Mancosu scored in the second half as the Montreal Impact beat the visiting Red Bulls, 1-0, on Sunday in the opening match of their M.L.S. Eastern Conference semifinal.
The second leg of the semifinal, a two-match, aggregate-goals series, is next Sunday at Red Bull Arena. The Red Bulls will be without forward Omer Damari, a substitute who received a red card in injury time after a hard slide into Calum Mallace.