We know Playoff contenders generally avoid upsets.

But typically they survive 1 or even 2 scares, occasionally against unranked or at least substantially lower-ranked teams.

Last year, national champion Clemson survived two upset bids. One involved controversy (Texas A&M), the other a bit of good fortune (Syracuse).

The Tigers needed their 3rd-string QB to complete a 4th-down pass to rally past Syracuse, at home. Who knows what happens to the Playoff race if that pass falls incomplete.

Notre Dame squeaked past Vanderbilt. Lose that, and the Irish’s Playoff hopes would have expired in Week 3 instead of in the semifinal against Clemson.

Oklahoma needed overtime (overtime!) to sneak past Army. Oklahoma was a 29-point favorite — and only scored 28 points.

It happens.

Will it happen again in 2019? Will an upset bite a contender like it did Ohio State in 2018? Here’s a look at 1 game that has the greatest trap potential for each of these 5 Playoff contenders and preseason Power 5 conference favorites.

Clemson (ACC): at N.C. State

Most people will point to Syracuse. The Orange beat Clemson 2 years ago and nearly beat them last year. I think, by now, Syracuse has the Tigers’ attention. The fact the game is in Syracuse will only help Clemson’s preparation.

Motivation won’t be an issue against Texas A&M, Florida State or South Carolina. Talent will overwhelm just about everybody else.

Even Clemson’s most talented teams have had trouble putting away the Wolfpack. The 2015 team that played for the national title gave up 41 points to the Pack. Only Alabama scored more against that defense. The 2016 national championship team needed OT to get past the Pack in Death Valley. The 2017 team won by a touchdown. Last year, N.C. State entered with lots of hype, an aspiring NFL QB and a ranked team. It was the ACC’s version of Georgia at South Carolina. Clemson took notice, and blew them out 41-7. Trevor Lawrence had his first 300-yard game. N.C. State is starting over a bit in 2019, back to its usual pesky, underdog status. Those teams typically are the Pack’s most dangerous.

Ohio State (Big Ten): at Indiana

First Purdue, now Indiana? In football?

Three things to keep in mind: First, Indiana’s offense typically is better than its overall team. Offense has rarely been the Hoosiers’ biggest problem under Tom Allen.

Second, this will be Justin Fields’ third career start and first on the road. IU QB Peyton Ramsey had a career day at OSU last year, throwing for 322 yards and 3 scores. IU will have the edge in experience at the game’s most important position.

Third, IU has the edge in motivation. There won’t be a player on either sideline who was alive the last time Indiana beat Ohio State. The winning streak is 24 games. But it has been 31 years since IU actually won.

There’s no way new coach Ryan Day can convince his Buckeyes that these Hoosiers are capable of ending that streak in Week 3, either. That’s how upsets happen.

Oklahoma (Big 12): vs. Houston

The Cougars aren’t showing up in many way-too-early Top 25 polls, but they’ll enter 2019 with one of the most dynamic QBs in the country.

D’Eriq King will find the end zone against the Sooners. Remember, he had accounted for 50 TDs — most in the nation — when he suffered a knee injury in mid-November that knocked him out the rest of the way.

This game could become a shootout, and as explosive as Oklahoma’s offense has been, it’s still going to be Jalen Hurts’ first game in this system.

I’ve said for 2 years that the American Athletic Conference is closer to the Pac-12, if not better at the top, than the Pac-12 is to the rest of the Power 5.

This is Houston’s chance to prove that point.

Oregon (Pac-12): vs. Auburn

Two things: First, I don’t really believe Oregon or anybody else in the Pac-12 is a Playoff contender. The gap between their league and the others has grown. Georgia, Michigan, Texas, perhaps Notre Dame all appear to be more Playoff-ready. But I wanted to limit this to one team per Power 5 conference, so Oregon gets the reluctant nod out of the Pac-12, which hasn’t won a Playoff game since Oregon took out a vastly overrated Florida State team in 2014, and hasn’t been to the Playoff in the past 2 seasons.

Second, I’ve already put Oregon on upset alert in the opener against Auburn. I think the Tigers will control both trenches, offsetting whatever advantage the Ducks have in NFL prospect Justin Herbert.

Oregon is a slight favorite.

Even if the Ducks survive, this still is a team that lost 4 Pac-12 games last season. Most of the Pac-12 North is starting over at QB. That’s one reason the Ducks are receiving so much preseason love, but there’s little actual evidence that the Ducks are better than Washington State or Washington, both of which are breaking in new starting QBs. In Washington’s case, it’s former 5-star Georgia signee Jacob Eason. The Ducks face them in consecutive weeks in late October.

Alabama (SEC): at Mississippi State

Honestly, Alabama is so good it only loses to ranked teams. Seriously, since losing to Louisiana-Monroe in 2007, Alabama has lost 16 games — 15 against ranked teams. The only unranked team to beat Nick Saban in that span was rival Auburn in 2007 — a week after the ULM debacle.

However, the Tide are not immune to close calls. Last year was a tad ridiculous, but the 2017 national champions struggled at unranked Texas A&M and needed fourth-quarter heroics to rally past lower-ranked Mississippi State. The 2015 national champions needed a Derrick Henry TD run with 2 minutes left to beat an unranked Tennessee team that lost to Arkansas earlier and walked out of Neyland Stadium that afternoon 3-4.

Still, the talent usually and eventually outweighs whatever motivational lapses there might be.

Texas A&M and LSU will be highly-ranked have have the Tide’s full attention. Auburn is Auburn.

Mississippi State could be trickier than it needs to be. Transfer QB Tommy Stevens could be a game-changer Joe Moorhead needs, and the Tide will be coming off an always emotional LSU game, and traveling to Starkville. There’s next to no chance Saban will be able to convince his team that this MSU team, without its 3 first-rounders on defense, is as dangerous as the team it dominated last year.