Four games into this season, we don't know yet what the USC football team is -- but we at least know what it can be.

These Trojans have strung together enough impressive stretches on both sides of the ball to justify whatever expectations anyone wants to have at this point. They've also not shown yet -- outside of beating up on Utah State -- that they can do that for four straight quarters.

That was the reality again Saturday as No. 13-ranked USC turned the ball over three times in the first half and dug an 11-point deficit before reeling off 28 unanswered points after halftime to celebrate a 38-21 victory over Wisconsin in the Coliseum for the program's first Big Ten win.

So is USC (3-1, 1-1 Big Ten) the team that was trailing in the second half against all three power-four opponents -- LSU, Michigan and the Badgers -- or is it the team that asserted itself late in each of those games, winning against LSU and Wisconsin and narrowly pulling it off on the road against the Wolverines as well?

It seems like these Trojans are an equal dose of both -- imperfect enough to need to overcome lulls but with enough top-end potential to actually consistently do so -- and that fans may just need to strap in for some more wild rides to come.

RELATED: Game Breakdown: Full recap and highlights from USC's win over Wisconsin | Everything Lincoln Riley said after the win | WATCH: Postgame interviews

"At halftime, it was very player-led driven. The coaches kind of let us do our thing. They don't really step in too much when it comes to motivating us. The fire in the locker room was like, man, you know that's not us out there. Like, we're not playing like ourselves," linebacker Mason Cobb said. "For us, it's just keep swinging. I think that's our identity this year is no matter what happens, man, we're not going to ever lay down. ...

"We just keep swinging, keep swinging until the clock runs out."

The formula was a little different this time but similar enough to feel like we'd see this story already.

Wisconsin (2-2, 0-1) struck for some early explosive plays (just like LSU, just like Michigan) and the Trojans did themselves no favors in the meantime.

-Badgers backup quarterback Braedyn Locke hit Vinny Anthony II for a 63-yard touchdown.

-USC quarterback Miller Moss threw an interception in Wisconsin territory on one of his worst passes of the season -- lobbing the ball into tight coverage with a big defensive back right on smaller receiver Zachariah Branch.

-The Trojans muffed a punt that bounced through Branch's legs with Jaylin Smith unsuccessfully trying to dive on the loose ball -- Wisconsin recovered and scored the next play on an 18-yard Tawee Walker touchdown run.

-A false start by right guard Alani Noa on fourth-and-1 from the Wisconsin 19 forced USC to settle for a field goal.

-Locke connected with Bryson Green for a looping 35-yard completion that reserve cornerback DeCarlos Nicholson had plenty of opportunity to make a play on had he ever taken notice of the ball in flight. That led to an eventual 4-yard Walker touchdown run and a 21-10 lead.

-And then Moss was sacked and stripped with USC again deep in Wisconsin territory at the 22.

"I thought we did a great job in the first half moving the ball, kind of like coach said -- we just had some critical errors that slowed us up. I think we had like 250 yards of offense and 10 points in a half, which is kind of ridiculous when you look at it," Moss said. "... The second week in a row we've started slow offensively, which is unacceptable going forward. We're going to play teams where that's really going to hurt us and it did the week before, so we've got to get that addressed."

Running back Woody Marks was asked what coach Lincoln Riley's message was at halftime ...

"We done see this before. Ultimately you don't want it to be that situation, but we done seen it before and this time we had to come out with the win," Marks said. "The togetherness is unbelievable. I think this team is very close."

Wide receiver Duce Robinson seconded that point

"It feels like this year when we do face adversity it brings us closer, and obviously when we're closer we play better," he said. "So these past couple games we've seen adversity -- and we've seen a lot of adversity -- but I think we've showed that we're able to overcome that."

They have and they indeed did Saturday.

And again, the formula remained similar -- the defense tightens up and the offense feeds off Moss.

In that season-opening win over LSU, D'Anton Lynn's defense made notable adjustments, shutting down star wideout Kyren Lacy the rest of the game after he had 94 yards and a touchdown in the first half. With that, LSU scored just 10 points the rest of the way while Moss kicked off the comeback with an impressive 28-yard touchdown pass to Ja'Kobi Lane and made big plays down the stretch.

Last week at Michigan, Lynn's defense reeled off six straight stops from the end of the second quarter until the Wolverines' ultimate game-winning drive, including four three-and-outs and a forced fumble. Moss rallied the offense after a sluggish first half and eventually put USC on top late -- briefly -- on a 24-yard touchdown strike to Lane. That comeback didn't hold in the end, but this one would.

Once more, it started with the defense. Wisconsin had that 11-point lead and got the ball to start the second half, but USC forced a quick three-and-out.

"We were just relaying the message that we're up first to start the half, so the way we do things coming out, that sets the tone and it did," defensive end Jamil Muhammad said.

After a USC three-and-out, the Trojans caught a break when Wisconsin muffed a punt giving the hosts possession at the Badgers' 30. Eventually, that Moss to Lane connection delivered again on a touchdown pass on third-and-goal from the 6 -- their second TD hookup of the day -- to close the gap to 21-17.

The defense followed by stuffing Walker for no gain on fourth-and-1 from the USC 33, continuing to be characteristically stout in such situations.

"It's fourth and short, I mean it's going to be physical ball. So we know we got to nut up and make the play when it's fourth-and-1," safety Kamari Ramsey said, drawing a laugh from his head coach and the rest of the room.

"That's a very honest answer," Riley quipped.

And at that point it was pretty much all Trojans the rest of the way.

Moss put USC ahead on another third-and-goal, finding Robinson in the end zone for an 8-yard touchdown, the defense delivered another three-and-out with Ramsey delivering a bone-jarring hit on receiver Will Pauling to stop him for a loss of 2 on third down, Moss wowed the crowd with a spin move and withstood a big hit and hard fall on his way into the end zone for a 7-yard touchdown run, and Cobb punctuated the strong second half with a 55-yard interception return for touchdown late in the fourth quarter.

Riley was asked what fueled the second-half resurgence and he joked, "Just a really, really good speech."

Nobody laughed harder at that than Moss, sitting next to his coach at the postgame press conference.

"It wasn't that good," Riley said. "It was these guys. I think we came in just knowing we simply beat ourselves in a lot of ways. And Wisconsin made some good plays ... but we gave up explosive plays, we didn't stop the run in the first half. We moved the ball pretty well offensively, but obviously had the two turnovers in plus territory and then we had the big special teams play that got them momentum. We just really didn't do anything very well, but we felt like a lot of it was under our control and we kind of laid out exactly what we felt like the second half should look like. ...

"To have the first half go the way it did and to come back and play that well just says a lot about the character of the guys in this room. We're going to battle, we're not going anywhere, we don't panic and that's a good quality to have because when you play the schedule we play you're going to have some ups and downs. You've got to be incredibly resilient. So far we have been that."

Moss is now 4-1 as a starter and could be 5-0, having led a late go-ahead touchdown drive in that lone loss, at Michigan.

He finished 30-of-45 passing for 308 yards, 3 touchdowns and an interception plus his rushing touchdown on Saturday, and it's clear some significant percentage of USC's penchant for second-half moxie comes from its steely QB.

"He had some tough plays. The one thing we say in that room and always have is show me a tough team and I'll show you a tough quarterback, show me a soft team and I'll show you a soft quarterback. You've got to have it," Riley said. "But it's not just quarterback -- it's all over the field. You got to have that. You can have a couple individually tough guys, but is the group, is that something when you watch the entire team play that you feel that? That's something that I think this team has a lot of right now. He's a good example."

Marks, meanwhile, gave the player's perspective on why this team feeds off Moss.

"He's a very tough person. I think every time he gets knocked down he always gets back up no matter what. I think that's the mentality you have to have. He's the leader of this team," he said.

Lane put it even more succinctly.

"He's a dawg and played like it," he said.

Lane, meanwhile, had his best game yet with 10 catches for 105 yards and 2 touchdowns, and his first TD from Moss -- a 32-yard connection into tight coverage to start the game -- was a thing of beauty.

"Jak's special. everyone on the team knows it, we've all seen it throughout his entire career at 'SC, so just to be able to see him get on the big stage and be able to perform the way he does, show out, it's really cool," Robinson said of his fellow wideout.

But USC has had good quarterback play -- the best of the best actually with Caleb Williams the last two years. It's always had great receivers.

What's different about this team is the defense.

After Wisconsin scored touchdowns on three of its first five possessions to jump out to that double-digit lead, here's how the rest of the Badgers' offensive series went: punt, punt, turnover on downs, punt, punt, pick-6, turnover on downs.

That's the reason to ultimately believe in this team and its potential to compete for a Big Ten championship and College Football Playoff berth.

For whatever explosive plays it gives up, Lynn's group has now shown in every game this season -- including the 48-0 shutout over Utah State -- that it is capable of adjusting and delivering long stretches of suffocating defense.

That's why this Trojans team is more equipped than any recent iteration of shaking off early miscues or stumbles and having a strong belief that it will give itself every opportunity to turn the momentum and the game.

Even USC's offensive stars will be the first to acknowledge that.

"They play a really tough brand of football. I think they really embody what we want to be about. It's a luxury as an offense to have," Moss said.

Said Marks: "I think defense wins championships and offense sells tickets."

These Trojans have the talent and means to at least let fans believe both could be possible.