TORONTO — McLeod Bethel-Thompson delivered a stunning conclusion to his first CFL start.

Bethel-Thompson's 23-yard TD strike to Armanti Edwards with one second remaining rallied the Toronto Argonauts to a stunning 42-41 victory over the Ottawa Redblacks on Thursday night. Edwards' catch capped an 11-play, 86-yard march engineered by Bethel-Thompson, who was 25-of-37 passing for 302 yards with four TDs and an interception in his first game as a CFL starter.

He was especially sharp in the second half, completing 18-of-25 passes for 233 yards and the four TDs.

"My teammates held me up the whole game, they carried me the way," a modest Bethel-Thompson said afterwards. "All I did was my 1/12th and sometimes I did half of my 1/12th.

"We didn't play our best game, I know I didn't play my best game in the first half. But there was no give up, there wasn't a single blink. We definitely needed this."

Diontae Spencer's 88-yard punt return TD at 10:25 of the third gave Ottawa (4-3) a seemingly insurmountable 38-14 advantage. Spencer's electrifying run came after Toronto opened the second half impressively as Bethel-Thompson hit S.J. Green on a five-yard TD pass at 3:19 to cap a 60-yard, eight-play march.

Ottawa countered with a 64-yard, 10-play drive that resulted in Lewis Ward's 17-yard field goal at 9:01 before Spencer made it a 24-point contest.

Toronto (2-5) snapped a three-game losing streak in its first contest against an East Division opponent before a BMO Field gathering of 11,857.

Bethel-Thompson, after throwing for 122 yards in the third, found Green on an 11-yard TD pass at 1:12 of the fourth to cut Ottawa's lead to 38-26.

Ward's 14-yard field goal at 4:18 put Ottawa ahead 41-26. But after Zack Medeiros's 32-yard field goal at 8:57, Bethel-Thompson hit James Wilder Jr. on a 20-yard TD pass at 11:34 to pull Toronto to within 41-36.

The scoring play was set up by Martese Jackson's 70-yard punt return.

Toronto began its final drive at its 24-yard line with 1:45 remaining. Wilder Jr. said in the huddle there was no doubt in his mind Bethel-Thompson was behind the wheel.

"He took the offence by charge and made it happen and got a team win," said Wilder Jr., who ran for a game-high 73 yards on 17 carries. "He just picked it up, he just led us down the field.

"He's a general, that's what the quarterback is. He showed a lot today. I always knew it but I guess he showed you all."

Toronto played a terrible first half, committing four turnovers in falling behind 28-7. The Redblacks were able to convert fumbles by Wilder Jr. and Jackson in touchdowns in storming out to the 21-point advantage.

Redblacks' starter Trevor Harris was 18-of-21 passing for 245 yards in the half while Bethel-Thompson completed 7-of-12 passes for just 69 yards.

But thanks to an error-free second half, the Argos head into their bye week riding a huge momentum swing.

"We're not going to anoint ourselves with one win but I think we gave ourselves an opportunity to find out a little bit more about ourselves," Trestman said. "We just know we have something inside of us we can start with next week that we weren't able to see in the earlier games.

"We did not play a clean first half with turnovers and mistakes that were really costly. For 30 minutes we probably played our best football in some regards."

The 33-year-old Green led the Argos receivers with nine catches for 134 yards and two TDs.

"We put drives together when we had to," Green said. "We had competitive greatness and we developed some backbone along the way.

"He (Bethel-Thompson) was prepared tonight and it showed. You expect things like this when a guy of his calibre comes in."

Harris was 27-of-35 passing for a season-high 381 yards and two TDs for Ottawa. Spencer finished with eight catches for 145 yards and a touchdown while returning three punts for 104 yards and a score.

Ottawa head coach Rick Campbell said his club was unable to put Toronto away in the second half. The Argos outscored the Redblacks 35-13 in the final two quarters and by a 22-3 margin in the fourth quarter alone.

"We didn't make enough plays to win it," he said. "We had opportunities all the way down literally to the last second of the game to come up with enough plays to win it and we didn’t.

"I'll give them credit. They made more plays than we did at the end and won the game."

Campbell also praised Bethel-Thompson's play in the second half.

"He made some good throws and their receivers made some good catches," he said. "That's why you've got to play the game for 60 minutes, literally.

"That's proof of that tonight."

Anthony Cioffi, Dominique Davis and Brad Sinopoli had the other Ottawa TDs. Ward had three converts and two field goals while Brendan Gillanders added a two-point conversion.

James Franklin ran for two touchdowns for Toronto. Medeiros booted three converts and a field goal.