Hassoun Camara scored on a header in the first half as Montreal held on for a 1-0 win over the San Jose Earthquakes in the group stage opener for both clubs Wednesday.
Camara jumped to redirect Bernardello's free kick past San Jose goalkeeper David Bingham 16 minutes into a rainy first half before a crowd of 15,115 at Saputo Stadium.
Bernardello started in his Impact debut and made his presence felt early at both ends of the field.
"The important thing is the team won and played well and I'm happy for the victory," the 27-year-old Argentinian midfielder said in Spanish through a translator. "I was expecting a more physical game and it went well under the circumstances. I did my best to give good balls on the attack and I'm happy that everything went well and that everything is heading in the right direction."
Impact goalkeeper Evan Bush stopped a San Jose penalty five minutes before Camara's goal and went on to record the shutout for Montreal, which last qualified for the Champions League in 2008.
Bernardello, who signed on July 23 as the MLS team's second designated player, headed clear a ball in the defensive box seven minutes in, shortly before a steady rain began to fall throughout the rest of the opening half.
"I'm really impressed with him," Impact forward Justin Mapp said. "He's a spark in there. He wins balls and he's good with the ball. He had a great set piece to set up Hassoun so I think he's definitely going to help the team, and you saw that tonight."
Puerto Rican referee Javier Santos also made his presence felt early and often. He showed Montreal's Collen Warner a yellow card and awarded the penalty to the Earthquakes when he ruled that the Impact midfielder had blocked a San Jose free kick with his arm.
The early jeers from Santos' tight officiating were blown away by a huge ovation when Bush dove to his right to stop a low shot from the spot by Alan Gordon.
"Penalties, you've got to decide to react or decide to go one way," Bush said. "For me I decided to go that way and it turned out that maybe I got a little bit lucky in the way I went and made the save."
Sam Garza had another Earthquakes' scoring opportunity early in the second half, but his header went wide of the left post.
"Obviously we leave the field a little bit disappointed," San Jose coach Mark Watson said. "I felt overall our performance was good, a good road performance. Obviously a key moment of the game was the penalty save. It would have given us the lead and something we could have hung on to for the rest of the game but even after the goal I thought we responded well and had a bunch of chances."
Garza entered as a substitute in the 43rd minute to replace Martin Chavez, who was carried off the field on a stretcher moments earlier after he was injured on a hard tackle.
Impact captain Matteo Ferrari headed a shot off the top of the crossbar in the 65th minute on Mapp's centring pass from the right corner.
Montreal, which is third in the MLS Eastern Conference with a 10-6-5 record, beat the Vancouver Whitecaps in the Amway Canadian Championship final to claim its eighth Voyageurs Cup.
San Jose is one of four American MLS teams in the CONCACAF Champions League. The Earthquakes, who qualified as the 2012 MLS Supporters Shields winners, are eighth in the West with an 8-9-6 mark.
"Unfortunately the PK could have made a big difference for us," San Jose's Mehdi Ballouchy said. "The thing that probably hurts me the most is giving up a set piece. I think if we gave up a great goal we walk out of here feeling better about it. But losing on a set piece on the road kind of having played well enough, that sucks."
The 24 teams in the tournament are divided into eight groups of three, with the winner of each group advancing to the quarter-final stage.
The Impact, who are in Group 5, travel to Guatemala to play C.D. Heredia on Aug. 21. Montreal visits the Earthquakes in San Jose, Calif., on Sept. 17 before hosting Heredia one week later to close out the group stage.
Toronto FC, which represented Canada in each of the last four CONCACAF Champions League tournaments, made it to the semifinals of the 2011-12 competition, losing to Mexico's Santos Laguna.