MONTREAL — Andrew Wenger headed in a goal just before halftime and Felipe Martins added another for the Montreal Impact in a 2-0 victory over the Philadelphia Union.

Wenger, the top pick in the SuperDraft, got the start because designated player Marco Di Vaio was in Italy, where a prosecutor has called for the former Bologna star to be suspended one year for failing to report alleged match fixing in a scandal that has shaken Italian soccer.

The 21-year-old Wenger looked ready to take up the challenge, leaping into the air to head in a goal on a set play off a corner kick just before half time.

“I don’t think the replacing Di Vaio thing is much of a story,” Wenger said after his fourth goal in 14 MLS games. “I’ve played out there by myself before.

“It’s another game where, as a rookie, I’m trying to prove I can play in this league and keep progressing.”

Martins struck in the 79th minute, thrusting forward to head in Hassoun Camara’s cross.

Goalkeeper Donovan Ricketts and the team got its first clean sheet since a 2-0 win at Kansas City on May 5, and only its third of the season.

“The good thing is we didn’t allow a goal, that’s the first step,” said defender Matteo Ferrari. “But I think we didn’t do well as a team.”

The Impact (9-13-3), who are 8-3-2 at home, moved past the Columbus Crew into sixth place in the Eastern Conference and opened a seven-point lead on eighth-place Philadelphia (7-11-2). However, both of those rivals hold five games in hand on Montreal.

The Impact may get more bad news this week as central defender Nelson Rivas was sent off along with Union forward Jack McInerney in the 69th minute after a shoving match, leaving both clubs with 10 men to finish the game.

Replays showed Rivas head-butting the Philadelphia player, so he may get more than the automatic one-game suspension for a red card, although there was embellishment on both sides of the melee.

“One’s a head butt and one’s a very innocent push,” Union coach John Hackworth said. “I can’t for the life of me figure out how we’re not up a man for the last 22 minutes.

“It’s unfathomable to me. I looked at the video. Jack doesn’t even really push him.”

The Impact’s win avenged a 2-1 loss in Philadelphia on July 14 on Carlos Valdes’ goal in stoppage time. It was Montreal’s second victory in a row after a 3-1 decision over New York a week earlier.

The Union missed two prime chances in the first half as Lionard Pajoy hit a post and Jack McInerney was stopped from in close off a corner kick.

“Those two missed chances came back to haunt us,” Hackworth said. “Then we opened the second half and have a great combination play through the middle and miss another one.

“If you don’t (score) you can’t win.”

NOTES: Di Vaio, who faces a one-year ban for failing to report match-fixing while with Serie-A club Bologna, is to return to Montreal on Sunday. A decision in his case is expected next week. ... The Union’s new acquisition, Malian defender Bakary Soumare, was expected to make his debut but wasn’t even in the 18-man lineup.