LOS ANGELES — John Houston Jr. has experienced it before.

The fifth-year senior linebacker and leader of the USC defense redshirted on a team that, in 2015, dropped two conference games by Oct. 8. The Trojans rallied, adjusting to a coaching change and building an impressive home-field winning streak that lasted three years, en route to their first Pac-12 Championship Game. A year later, USC again recovered from a 1-3 to win the Rose Bowl Game.

"You can always be down one week then up the next week," Houston said following USC's 41-14 rout of Arizona at Los Angeles Memorial Coliseum. "Zach [Banner], Mike Hutchings, all the leaders we had, I took that and try to mirror their leadership and put my own critique [relevant to the present]."

The lessons of those seasons resonate in holdovers like Houston, emulating the approach they witnessed as underclassmen and imparting it to a young crop of Trojans. Head coach Clay Helton, who assumed leadership in 2015 from dismissed Steve Sarkisian amid that 1-2 Pac-12 start, cites the turnarounds of that season and '16 as a precedent for this year's team.

A return to Levi's Stadium and the Pac-12 Championship Game — USC's third such appearance in five seasons, if it comes to fruition — provides the Trojans a lane back to the Rose Bowl. It requires no scoreboard-watching or Charlie Day corkboard scenarios.

"Six games to win the Pac-12 South, and win a Pac-12 championship," said defensive line Nick Figueroa. "We had some highs in our first half of the season, we had some lows in our first half. Now, it's like a whole new season."

"Just do your job," said defensive lineman Caleb Tremblay. "Focus on the next game up. We've got Colorado next... Can't really look ahead, because that's how you get caught."

A team without a road win yet on the season especially should not overlook a final stretch with 3-of-5 games on the road, starting Week 9 in Boulder against Colorado. But the reality is if USC is the only team in the Pac-12 South that controls its destiny.

An interesting parallel between 2015 and '19 for USC is in both seasons, the Trojans scored a home win over a Utah team highly ranked in the national polls and harboring legitimate College Football Playoff aspirations. That win proved pivotal for USC in 2015, with the two teams tying atop the South.

Following the 2019 installment, Utes head coach Kyle Whittingham publicly repeated a proclamation he made privately to his team: "No one is coming out of the South undefeated."

His words proved almost immediately prophetic. One week after knocking off Utah, USC went to Washington and lost, 28-14. The Huskies handed the last undefeated team in the division its first Pac-12 blemish two weeks later when they routed Arizona.

With Arizona taking a second conference loss to USC in Week 8, a few hours after Utah finished a 21-3 throttling of Arizona State, it's now USC and Utah tied atop the loss column. USC, of course, holds the tiebreaker.

When Whittingham noted the likeliness of a wide-open South, he wasn't exactly going out on a limb. Not only has no team ever gone untouched through either division since the Pac-12's inception, but three South representatives since the conference championship game's inception in 2011 lost three games (not counting 2011 UCLA, which advanced by default as a result of two-loss USC's NCAA postseason ban): UCLA in 2012, USC in '15 and Utah last year.

"We have a lot of football left," defensive back Julian Blackmon said on Sept. 20. "We know what happened last year, so we just have to be ready for the next game. We play Washington State next. It’s time to be over this game already."

The Utes moved on effectively indeed. Their three wins since facing USC came by a combined 88 points. The seven and three points Utah limited Oregon State and Arizona State to mark a program record since it joined the Pac-12, as Athlon Sports' own John Coon notes.

Utah's wins over Oregon State and Arizona State mark the first time that the Utes have held consecutive Pac-12 opponents to single digits. #Utes #Pac12FB — John Coon (@johncoonsports) October 21, 2019

And the record-setting extends to individual Utes, with running back Zack Moss — who missed almost the entirety of the USC game — making history in the Arizona State win.

Congratulations to @PresMoss2 on an outstanding career. We have been so lucky to have him as part of this team. Looking forward to watching him break a few more records! https://t.co/J5uiVg7cLJ — Kyle Whittingham (@UtahCoachWhitt) October 21, 2019

Utah's playing its best football since last October, which may or may not be reassuring. Following that impressive stretch a year ago, the Utes lost Moss, quarterback Tyler Huntley, wide receiver Britain Covey, and linebacker Chase Hasen all to injury. They still won the South for the first time in program history, albeit with a huge assist from the Oregon Ducks — something Utah might need again in 2019.

Were it not for the loss of those players, it's not unreasonable to suggest Utah would have reached the Rose Bowl. After all, its loss to Washington in the Pac-12 Championship Game came by just one touchdown, scored as a result of the offense's inability to move down the field.

And, well, Huntley's health is a question mark following the Arizona State win. Should Utah get past a recently stumbling Cal bunch at home in Week 9, the Pac-12 Championship Game rematch at Washington awaits. The Huskies hold a four-game winning streak over the Utes, which each of the four coming down to the wire in highly competitive, sometimes weird contests.

Nov. 2 could be the most pivotal date in the Pac-12 South race. Utah-Washington should go final at Husky Stadium just before USC and Oregon kick off at the Coliseum. The Ducks have a commanding lead in the North and should walk into Santa Clara for the first time since 2014, barring a disastrous final month.

But as Blackmon said a month ago, even at that point, there's "a lot of football left." No team from the South is technically eliminated, though three-loss Colorado might want to borrow Charlie Day's corkboard. For everyone else, the South remains open. Even UCLA, which opened the season 1-5, still gets both Utah and USC in head-to-head contests.

And for USC and Utah to continue setting the pace, they have to get past Colorado and Cal in the coming week. The unpredictable Pac-12 offers no time to look ahead — but it's in the contenders' best interest to look back at the conference's precedent for wild races.

— Written by Kyle Kensing, who is part of the Athlon Contributor Network and a sportswriter in Southern California. Follow him on Twitter @kensing45.

(Top photo by John McGillen/USC Athletics, courtesy of usctrojans.com)