The past two seasons, six NFL underdogs won their games outright opening week. Five of them won in 2015. In the parity-driven NFL, there are always upset picks to be had for massive payouts -- you just need to know what to look for. Before you pick your NFL upset of the week, you need to hear what expert handicapper Mike Tierney has to say.

No one knows the NFL like the "Top Dog." A national sportswriter whose work has appeared in the New York Times and Los Angeles Times, he has reported from seven Super Bowls. He has his finger on the pulse of the league.

Tierney excels both against the spread and straight-up. Now, with the 2018 NFL season finally here, Tierney has studied the matchups and has revealed a pair of confident upset picks for Week 1. We can tell you one of those is on the Bengals, a three-point underdog at Indianapolis. A $100 wager on the Bengals would net you $120.

Tierney knows many national pundits are projecting the Bengals to finish behind the Browns in the AFC North. The 2017 couldn't have gone much worse for Cincy's offense, either. It took until Week 3 to score its first TD, the team was held to single-digits five times, and the Bengals finished dead-last in yards gained and 26th in points scored. Despite the poor offensive output, the Bengals still finished 7-9 thanks mostly to a defense that ranked fourth in red-zone TD percentage.

The team was aggressive in shoring up a porous offensive line this off-season. As far as Week 1 at Indy goes, Tierney notes the experience of coach Marvin Lewis and QB Andy Dalton -- just one year removed from a Pro Bowl-caliber year -- is a big key compared to the Colts' leadership of first-year coach Frank Reich and QB Andrew Luck, who hasn't thrown a meaningful pass in more than a year.

While Indy's 31st-ranked offense from a year ago should improve to some extent with Luck under center, the 29th-ranked defense from a year ago wasn't overhauled, posing questions at every layer.

"The Colts' defense was worse than all but two teams a year ago. Yet somehow the Colts are favored," Tierney told SportsLine. "Too soon for that."

His other underdog pick is a team many experts, and Vegas oddsmakers, are overlooking, but Tierney points to two critical x-factors that he says turn this underdog into a favorite.

So what is Mike Tierney's NFL underdog pick of the week? Visit SportsLine now to see which underdog team shocks the world in Week 1, all from the expert who has crushed the sportsbooks with his NFL picks, and find out.