Boogie Ellis has found his basketball zen, as he showed Thursday night.

He was asked about the home game last season against UCLA, when he didn't score a point despite USC winning that rivalry game. He was asked about the two-point loss at UCLA earlier this month, when he committed a late offensive foul and missed the final shot of the game.

He addressed those moments the same way he did his 31-point outburst in leading the Trojans to a 77-64 win over the No. 8-ranked Bruins inside a packed Galen Center on Thursday evening.

"It's basketball -- you're going to have your highs, you're going to have your lows, but you always have to stay right in the middle," Ellis said. ... "This game has highs and lows. Tonight was a high. But it's a blessing, for real. I work hard for these moments."

The senior guard's steady inner metronome also helped him weather a tough first-half in this crosstown showdown, as he scored just 4 first-half points while missing all 5 of his 3-point attempts as the Trojans went into halftime with a 37-25 deficit.

Despite those early results, Ellis' confidence couldn't have been more palpable the rest of the game as he tied UCLA after halftime all by himself with 27 points -- knocking down 3 of 4 from long distance and all 10 of his free throws to finish with those career-high 31 points. He also had 6 assists and 0 turnovers.

"We changed our offensive style in the second half. Instead of trying to get ball movement, we just went right to Boogie and Drew [Peterson] and put them in isolation, had them create for themselves and others," USC coach Andy Enfield said. "Boogie, when he gets it going, he's really hard to guard because he can drive it, he can pass it and he can step back and shoot the deep 3. He played like a first-round draft pick tonight -- it was very impressive."

In the other postgame press conference, UCLA coach Mick Cronin was asked how "unexpected" Ellis' performance was ...

"Did you say how unexpected was it? About as unexpected as traffic tomorrow morning on the 405," Cronin quipped.

Ellis is now averaging a team-high 16.3 points per game for the Trojans while settling in comfortably to the role of team leader and offensive focal point.

Meanwhile, Peterson added 16 points and Kobe Johnson contributed 10 points, 5 rebounds, 5 assists and 3 steals as USC (15-6, 7-3 Pac-12) earned its first win over an AP top-10 opponent since 2017 while snapping a three-game losing streak in the rivalry series with the Bruins (17-4, 8-2).

"Me and Drew told the guys that we've been in this position before. We're the leaders, so we told them we can't panic -- we're going to come out, we're going to hit them in the mouth in the second half, forget what happened in the first half. We've been through it," Ellis said of the second-half about face. "Me and Drew have played in big games, played in big atmospheres, so it was really our job to calm the team down."

Enfield said the key was closing the gap early in the half, and indeed the Trojans wasted no time.

USC opened the half on a 27-6 run, hitting one big shot after another -- many from Ellis.

He spurred a run within the bigger run when he knocked down a short jumper, the Trojans followed with a stop and a Tre White 3-pointer, Kobe Johnson followed with a steal on the Bruins and Ellis hit a long step-back 3 from the left wing to cut the once double-digit deficit to 41-40 less than 6 minutes into the half.

A couple minutes later, Ellis was at it again. He scored on a layup, followed immediately with a steal on a lazy pass from UCLA point guard Tyger Campbell while feeding Reese Dixon-Waters for the fast-break layup, and Ellis then added another 3 for a 47-43 lead.

A Johnson 3-pointer and a Peterson dunk pushed the lead to 52-43.

UCLA didn't go away, of course, even drawing to within 2 points in the final minutes, but Ellis wasn't done either.

He used his devastating step-back move to drop in a short jumper to keep some separation at 58-54 with 3:33 remaining. Peterson hit one of his own near the end of the shot clock to make it 60-56 with 2:35 on the clock.

And after a pair of Johnson free throws and continued strong defensive play by USC, Ellis delivered the dagger with one more long heat-check 3 several feet behind the line and over Amari Bailey.

While the records aren't all that different -- and the results of the two-regular season meetings certainly show how competitive these squads are -- the Bruins were No. 8 in the rankings and the Trojans were unranked, not even receiving votes entering this week.

There's no understating how big this win is for USC's NCAA tournament resume, which was lacking a statement win.

"We need a big statement win. We almost had it at Pauley [Pavilion] three weeks ago, and we won a great game on the road at Arizona State on Saturday. Our team is playing very well -- they've improved a lot -- and that's what we like to see," Enfield said. "Now we have [freshman center Vince Iwuchukwu] back and he's a difference-maker with his length. He may not be a huge scorer right now, but he really creates problems with his length and his athleticism inside and he's a good rebounder. It's fun to see the progression of teams.

"This team, we weren't sure what we had, especially after the first game. We lost opening night [to Florida Gulf Coast] and we could have played anybody and lost that game, we were so bad. So we're very proud of our guys hanging in there and improving."

Said Ellis: "I mean, it's a good win, but we've still got work to do, still got work to handle. We've still got to get better. We can't get complacent just because we beat them. We can't lose any games that we're supposed to win. We've just got to lock in, don't get complacent and just keep going forward, keep getting better. ... Tomorrow's a new day, this will all be over. I'm going to enjoy it tonight."

USC and Utah are now just a game behind the Bruins in the Pac-12 standings with Arizona and Arizona State lurking at 6-3 in league play.

"That's the first goal in mind is to take care of the conference regular-season, then obviously the Pac-12 tourney and then potentially a tourney run," Peterson said. "But we're taking it a step at a time because each game weighs the same, so we've got to take care of next week, defend our home court again and like Boogie said, tomorrow's a new day and we've got to take care of next week."

What USC would like to see carry over from Thursday night -- aside from Ellis' sharpshooting -- was the crowd turnout inside Galen Center.

Enfield said it was one of the two best home crowds of his 10 seasons with the Trojans, and those fans were reciprocated with one of the best performances by this team and its best player all season.

"I thought last year's game [vs. UCLA] and this year's game were the two best [home] atmospheres we've played in in 10 years," Enfield said. "Last year and this year were as good as any place in the country. I've been coaching off and on for 28 years -- in the NBA and in college, coached in the ACC, I've been doing this for a long time -- and if you go to some of the arenas, our home crowd this year and last year the UCLA game was as good as anywhere I've ever been. And it's such a big advantage for our players.

"We would not have come back from 12 down at halftime without that energy the fans provided. We're very, very thankful of that."