TORONTO — Awkasi Owusu-Ansah and the Toronto Argonauts defence set the tone early.

Owusu-Ansah and Aaron Berry returned first-half interceptions for touchdowns to lead Toronto past the Montreal Alouettes 24-20 on Thursday night in the first CFL exhibition game for both teams. Neither squad was especially sharp offensively before a BMO Field gathering of 5,532 spectators. Then again, both teams didn't dress a number of their starters.

However Owusu-Ansah said it's always huge when a defence can score.

"It sets the tone for what we want to become this season," he said. "Whenever you can put points up on the board that's what is most important.

"When the defence can do it, it's definitely a plus."

A fact not lost upon Marc Trestman, who was in his first game as Toronto's head coach after spending the last four years in the NFL with the Chicago Bears and Baltimore Ravens.

"When a defence gets two scores, the analytics say you're going to have a pretty good chance to win," he said. "I think the biggest thing we got out of it is collectively as a team we went through the process of playing a full game and understanding a little bit more about the CFL."

While the game doesn't count in the standings, Owusu-Ansah said there's no substitute for winning.

"A winning locker-room is contagious," he said. "You want to create that environment, create the culture of winning games regardless of it's a pre-season or regular-season game."

Trestman agreed.

"When guys go out and are fighting for each other and are physically laying themselves on the line it's though to say it's an exhibition game," he said. "It's important to set a groundwork for winning, it's important to see what it feels like to win.

"We're not getting ahead of ourselves either, don't get me wrong. But we've got to start somewhere."

The Argos won't have long to enjoy the win.

"We're back to training camp (Saturday)," Trestman said. "We still have a real sense of urgency as we move into next week to figure out what our final roster is going to look like.

"Practice, as it has been, is going to be critically important this week."

Trestman's CFL return came against the team he led to two Grey Cup titles before heading to the NFL. Trestman spent five years on Montreal's sideline (2008-12), winning league titles in 2009-10 prior to becoming Chicago's head coach in 2013.

Trestman was fired last season as Baltimore's offensive co-ordinator. He returned to the CFL with Toronto, joining GM Jim Popp, who hired Trestman in Montreal.

"I didn't think about it (facing Montreal) during the game at all," Trestman said. "I made a point of going out early today and hugging and talking to just about everybody that was there when I was there.

"I got up real early to find space there to spend time with so many people and players I care about and consider family."

Montreal will host the Grey Cup-champion Ottawa Redblacks on Thursday night in the final exhibition game for both teams. Toronto visits the Hamilton Tiger-Cats next Friday night.

The Alouettes open the '17 campaign hosting the Saskatchewan Roughriders on June 22. Toronto's season opener is June 25 at BMO Field versus the Ticats.

Receiver Jimmy Ralph, a free-agent rookie from Alberta, had Toronto's lone offensive TD, a 10-yard catch from sophomore quarterback Cody Fajardo at 2:07 of the fourth quarter. That put the Argos ahead 24-9 after Montreal pulled to within 18-9 following Boris Bede field goals of 46 and 23 yards in the third.

After having a five-yard TD run nullified by penalty earlier in the fourth, Montreal rookie quarterback Matthew Shiltz hit George Johnson on a 13-yard touchdown pass at 13:07. The two then hooked up on the two-point convert to cut the Alouettes' deficit to 24-20.

Surprisingly, Montreal kicked off deep, giving Toronto the ball with 1:44 remaining at its 31-yard line. The Argos ran out the clock to cement the win.

Ricky Ray started at quarterback for Toronto, completing all three passes he threw for 26 yards before giving way to Drew Willy, who was 8-of-12 passing for 58 yards. Jeff Mathews completed 8-of-15 tosses for 110 yards and an interception before Fajardo finished 8-of-10 for 76 yards and the touchdown.

Vernon Adams Jr. played most of the opening half for Montreal, completing 4-of-12 passes for 64 yards with two interceptions. Jacory Harris was 9-of-15 for 110 yards and an interception before Shiltz came on in the fourth, going 6-of-10 for 69 yards.

Toronto's Lirim Hajrullahu booted two converts, a single and field goal.

Bede had four field goals for Montreal.