The Bears have spent all season trying to manufacture confidence for quarterback Mitch Trubisky. They had him look at TV tape and were encouraged when he talked to his high school and college coaches. They wanted him to drown out the outside noise, whether or not he turned off a single TV inside Halas Hall.

This week, though, Trubisky got his confidence the old-fashioned way: by playing well in his previous game. He was 29-for-38 for 338 yards with three touchdown passes and one interception for a 118.1 passer rating in a 24-20 victory Thursday. His best performance of the year — yes, that’s a low bar — came against the league’s third-worst pass defense. Entering the Thanksgiving game, the Lions had allowed the fourth-most yards and ninth-most points in the league.

“That’s the best replacement and best motivation that anybody can get in anything you do,” coach Matt Nagy said. “Your confidence goes with how you play and just how everything around you is. You’re seeing right now, whether it’s [wide receiver] Anthony Miller making great catches, whether it’s the line sticking onto guys in the run game, making that extra block in protection or overcoming penalties to be able to put yourself in a position to succeed.

“Having a win the way we had it and playing better and improving slightly each week, I think, is helping him out.”

Trubisky will need that extra boost of confidence Thursday. The Cowboys’ defense is a massive step up from that of the Giants and Lions, whom he beat a total of three times in November.

Entering Sunday’s games, the Cowboys had allowed the eighth-fewest points in the NFL.

How Trubisky processes success this week will be telling. He has had passer ratings above 100 two other times this year.

After the Redskins game, Trubisky dislocated his left shoulder after three throws against the Vikings. When he was able to start again, he lost three in a row.

After beating the Lions for the first time, he put up a 65.1 passer rating against the Rams and had a notorious sideline talk with Nagy as backup Chase Daniel took the field. The Bears said Trubisky had a hip pointer; he was a full participant in the next week’s practices.

There’s a balance, of course, between taking the positives from the week before and basking in them — just as there is in learning from the negatives and wallowing in them.

“It feels good,” Trubisky said. “You want to duplicate that feeling, and then you forget about it and move on and are even hungrier for this week. So we already forgot about this week. It was nice to get a win on Thanksgiving. But we play on Thursday night again, so we just have to prepare and stay mentally locked in and get after it again this week.”

The mental side of Trubisky’s preparation matters. The Bears have praised his practice performance for most of the season, only to watch him struggle on Sundays. Last week, the Bears didn’t hold a single strenuous practice before the Lions game — but he played well.

“I think if we’re locked in mentally, then that’s how it translates to the field,” he said. “Everyone knowing their jobs. Me knowing the timing of the routes, knowing the spots, seeing the defense pre-snap and just playing fast and not thinking.

“We get it down mentally, go out there and play. And hopefully you’ve just gotta put in the work and make sure to execute and do our jobs.”

The Bears like their quarterback’s mentality.

“Probably just focused,” Nagy said. “Less, I don’t know what the word is, less distractions. He’s just out there playing.”