First-round betting trends to know

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With the bracket for the 2017 NCAA tournament released, here is a look at the first-round seeding matchups from a historical betting perspective.

No. 1 seed vs. No. 16 seed

No. 1 seeds are 128-0 straight-up all-time against 16-seeds, but over the past four NCAA tournaments, top seeds are only 6-10 against the spread in this round. However, if the line is under 20, lean towards the favorite. Since the tournament expanded to 64 teams in 1985, No. 1 seeds are 14-5 ATS against 16 seeds when the line is 19.5 or lower, including 7-1 over the past 10 seasons.

No. 2 seed vs. No. 15 seed

Since 2008, this matchup is as even as it gets from a betting perspective. No. 2 seeds are 18-18 ATS against 15 seeds in that span, and in seven of those nine seasons, two favorites covered and two did not. However, No. 15 seeds have upset No. 2 seeds four times since 2012 (4-16 SU) after going 4-104 in the first 108 matchups. If the betting line is large, lean toward the underdog. No. 15 seeds that are getting at least 18 points have covered seven of the past eight times, dating back to 2008.

No. 3 seed vs. No. 14 seed

At least one 14-seed has upset a 3-seed outright in each of the past four NCAA tournaments. Big 12 teams have accounted for three of those losses, going 1-3 outright and 0-4 ATS against 14-seeds over the last two years. However, only two 14-seeds have ever advanced to the Sweet 16, and none since 1997 when Chattanooga did it. The other, Cleveland State in 1986, was actually favored in its second-round game against Saint Joseph's, making it the lowest seed to be favored in the NCAA tournament since 1985.

As for first-round matchups, No. 14 seeds that are at least 12-point underdogs against No. 3 seeds are 6-2 ATS over the last three seasons.

No. 4 seed vs. No. 13 seed

Over the past three seasons, No. 4 seeds are 11-1 outright against No. 13 seeds but only 5-7 ATS. Before that stretch, this is a matchup that traditionally leaned to the favorite. From 1990 to 2013, favorites were 54-41-1 ATS. Shorter underdogs have also had success in this matchup recently: Since 2012, No. 4 seeds that are favored by 7.5 points or fewer are 2-5-1 ATS with three outright losses.

No. 5 seed vs. No. 12 seed

The 12-5 pairing is famous for producing upsets, and that applies to the betting side as well. Since 2009, favorites are just 11-21 ATS, including 5-11 since 2014. A 12 seed has defeated a 5-seed outright in 18 of the past 21 seasons, and the series is tied 8-8 over the past four NCAA tournaments. No. 12 seeds are also the lowest seeds that have been favored in NCAA tournament games since 1985. Six 12-seeds have been favored over 5-seeds, though none have been since Rhode Island was a one-point favorite over Charlotte in 1999. In that game, fifth-seeded Charlotte "upset" 12th-seeded Rhode Island 81-70 as a 1-point underdog.

No. 6 seed vs. No. 11 seed

This matchup has been dominated by the No. 11 seeds in recent years. Since 2009, No. 11 seeds are 19-13 ATS against No. 6 seeds, but not all of those games have come as an underdog. An 11-seed has been favored over a 6-seed in five straight NCAA tournaments, with the favored 11-seed covering and winning in four of those five games, including Gonzaga beating Seton Hall last year. When No. 6 seeds are favored, they have struggled recently, going 3-6 ATS over the past three seasons.

No. 7 seed vs. No. 10 seed

Despite 11- and 12-seeds having great success in recent seasons, the chalk has done well in the 7-10 matchup lately. No. 7 seeds are 11-5 outright against No. 10 seeds since 2013, with favorites going 10-6. No. 7 seeds that were favored have been even more successful, going 10-1 outright and 7-4 ATS in that span. Last year was an anomaly for 7-10 matchups, as three of the No. 10 seeds were favored, the most in any tournament since 1997, with the favored No. 10 seeds going 2-1 outright and ATS.

No. 8 seed vs. No. 9 seed

Since 2009, this matchup has been all about the underdog; underdogs are 20-9-3 ATS. However, that doesn't simply mean to bet on the 9-seed. In that span, 14 9-seeds have been favored in this matchup, and only three have covered. Last year didn't quite live up to that trend, as all four 9-seeds were favored, going 3-1 outright and 2-2 ATS. When the line is within three points, the underdog has covered all 10 times since 2010, including last season when Saint Joseph's covered against Cincinnati and USC covered against Providence (despite losing outright by one point).