Nobody could have imagined the success USC and coach Andy Enfield would find in rebuilding the roster last offseason in large part around four mid-major transfers.

But those moves have paid off in some of the biggest moments these last couple months, and so it was perfectly fitting that this largely underrated, overachieving Trojans team would seize its biggest moment of all -- and the biggest moment for this program in 20 years -- while being led by two of those, well, underrated, overachieving transfers.

Isaiah White, who joined USC from Utah Valley, matched his season-high with 22 points on 8-of-10 shooting (4 of 5 on 3-pointers), and Tahj Eaddy, the sparkplug from Santa Clara, scored 20 on 7-of-11 shooting (3 of 6 on 3s) while hitting one of the biggest shots late to send the Trojans to an 82-68 win over Oregon in the Sweet 16 in Indianapolis on Sunday night.

With that, No. 6-seeded USC (25-7) is headed to the Elite Eight for just the second time in the modern era -- after earlier being among the final four teams in smaller tournament setups back in 1940 and 1954. The Trojans were making just their third Sweet 16 appearance since the early 1960s and now join their 2001 team in making it this far.

USC, which has won all three of its NCAA tournament games by double figures, will play top-seeded and undefeated Gonzaga (29-0) on Tuesday (4:15 p.m. PT) with a spot in the Final Four on the line.

RELATED: Watch the full postgame press conference with coach Andy Enfield and star of the game Isaiah White

"It's a big moment in USC basketball. It's our second Elite Eight in the last 60 years -- 2001 and obviously now. So this is a huge win for our players, our program, but at the same time our players, they're very mature, they do celebrate, they have fun, but we have another game to play on Tuesday and we'll go give it our best shot," Enfield said.

Speaking of that towering obstacle that now stands in the way -- a Gonzaga team that opened the tournament with a 43-point win over Norfolk State, beat Oklahoma by 16 and Creighton by 18 -- White was asked what the Trojans' confidence is that they can become the first team all season to beat the Bulldogs.

"I don't know about what everyone else is saying. All I know is this team is special and we believe we can beat anybody, so we're going to play our game, we're going to listen to what the game plan is and we're going to execute," he said.

This team is definitely special -- its place in USC basketball lore already secure based on the aforementioned limited history for the Trojans advancing this deep in March Madness.

And all of the reasons that make it so were on display Sunday night.

After beating Drake by 16 points in the first round of the tournament and blowing out No. 3 Kansas, 85-51, in the second round, the Trojans carried all of that momentum into the first half Sunday against No. 7 Oregon, building a 41-26 halftime lead that would keep growing to 64-43 midway through the second half.

USC's stingy defense continued for another game as the Trojans switched early to a zone defense to combat No. 7 Oregon's smaller lineups and held the Ducks (21-7) to 30.3-percent shooting in the first half and 37.7 overall for the game. USC had held Drake and Kansas to under 30-percent shooting in the first two rounds.

Then the rest of the equation was the continued ability to have the unheralded offseason transfer additions rise up in big moments, like White and Eaddy did Sunday.

They led the charge in that first half with 12 points each. It marked just the second 20-point game this season for White, who came in averaging 7.3 points per game, but he also had 13 points vs. Kansas so he's playing perhaps his best basketball of the season here on the biggest stage. For Eaddy, it was the latest leading performance for a player who has become the pulse of this team in many ways.

The lead was later at 69-49 with under 9 minutes left to play when Oregon rattled off 11 straight points and held the Trojans scoreless for 5:30 while suddenly adding a tease of suspense to the proceedings.

But Eaddy -- again, fittingly -- stopped that run with a 3-pointer and Evan Mobley soon followed with a thunderous power move through the lane and two-handed dunk to push it back to 74-60 with less than 3 minutes to play.

There would be no suspense after all.

"The energy of March Madness, the crowd and we know what's at stake -- it's do or die, so everyone is just going out there and laying it all out on the floor," White said of why USC is playing at a different level since the tournament started.

As for the significance of the moment, White used an apt term to put it in perspective.

"We were overlooked a lot. I know it's been a minute since the USC program has gotten to the Elite Eight, so we're making history and it just means a lot to this program. As a team, we're just super excited and we worked for this, so I'm glad that it's paying off," he said.

Again, this was not the usual recipe for building an Elite Eight team. USC returned two rotation players in sophomore forward Isaiah Mobley and sophomore point guard Ethan Anderson, both still developing offensive players, plus raw sophomore Max Agbonkpolo. The Trojans of course had 5-star 7-foot center Evan Mobley arriving as the new freshman centerpiece, but the rest of the rotation would be filled out with transfers like White, Eaddy, Drew Peterson (via Rice) and Chevez Goodwin (Wofford). To find four mid-major players who are all able to then prove themselves at the major conference level is an against-the-odds plan for roster reconstruction, but there's no disputing how it's come together.

Enfield, the Pac-12 Coach of the Year, deserves credit for that.

"I'm really proud of our players. To have such an unusual team, meaning we only had three returnees, and we didn't meet these guys until school started in late August. We had COVID restrictions and we couldn't even bring them on campus and could not work them out. So to have guys believe in our program says a lot about the players before us because we were an established program, they believed that they could come and help us this year with the opportunity of only three returnees, so everybody we recruited we could say, 'You'll probably get some playing time because we don't have anybody else on our team,'" Enfield said.

"So they took a chance to come here. ... Once training camp started we had to figure out the strengths and weaknesses because we just didn't know -- we had never coached these guys before. So we switched a lot of things defensively and offensively to try use our strengths because we had a brand new team. Our players bought in -- they bought in defensively first -- they're very mature, they're a lot of fun to be around and it doesn't happen too often, but it's hard to think of a day that we didn't enjoy walking into the gym and practicing and getting after it this year. ... I think you're seeing that in the tournament here. They play really well together and they're cheering for each other and they play well on both ends of the court."

White, for his part, was asked why he thinks that motley blend has worked so well.

"Probably just how everyone doubted us," he said. "Once we found out they had us sixth in the Pac-12 [preseason poll], I think we really came together just to prove everyone wrong. When everyone doubted us, I think we really latched onto each other and grinded."

It was 21-19 early on when USC really took control Sunday. Evan Mobley grabbed a rebound off an Agbonkpolo miss and threw down a put-back dunk to spark a surge. White followed a couple possessions later with a layup on a baseline feed from Mobley. At that point, White had scored 12 of USC's first 25 points.

The next time down court Eaddy pulled up for a successful 3-pointer in transition, Peterson then found himself wide open at the top of the key and knocked down another 3, and Eaddy followed the next possession with a second-chance driving layup after a missed 3. That made it 33-19.

White and Peterson hit back-to-back 3s in the early minutes of the second half to pkeep the pressure on and push the lead to 20 points at 52-32 before the Ducks later made their brief comeback attempt.

Isaiah Mobley added 13 points and 6 rebounds in the win, Evan Mobley finished with 10 points, 8 boards, 6 assists and 2 blocks, and Agbonkpolo chipped in 9 points off the bench.

Oregon got a game-high 28 points and 10 rebounds from Eugene Omoruyi and 21 points from Chris Duarte, but the Ducks couldn't match the Trojans' collective prowess this time. For that matter, USC is now 2-0 against Oregon this season despite ceding the Pac-12 regular-season title to the Ducks based on winning percentage when Oregon had to play two less games due to COVID cancellations.

That's in the rearview, though, and ahead of the Trojans is an opportunity to try to make even more history.

Asked if he could put in perspective what even reaching the Elite Eight will mean to his program in the big picture, Enfield took the answer a different direction.

"We haven't even thought about that, but it is the second Elite Eight in the last 60 years for USC basketball. That's a huge win for our program," he reiterated. "I think as we've built this thing with Jason Hart as associate head coach, Chris Capko and Kurtis Shultz, they've been with me all eight years, and the other staff members like coach [Eric] Mobley, we have a terrific assistant coaching staff that have tried to build teams year after year and develop players and I'm so proud of our coaches. I'm only as good a head coach as my staff and our players.

"When we only had three returning players this year, we had a lot of work to do, so this team is built with transfers, graduate transfers, freshmen and some returnees, and they meshed together. So my assistant coaches deserve a ton of credit for this."

There will be plenty of credit spread around when it comes time to look back on this unexpected, historical USC basketball season.