NCAA Tournament betting preview: 16 facts about the Sweet 16

1) Tennessee, Creighton, Alabama and Clemson have never made the Final Four. In fact, the schools have only ever made five Elite Eights combined. Since 1966, only one team — 1999 UConn — has won the championship in its first Final Four appearance.

2) This is only the fifth time since the NCAA Tournament expanded to 64 teams in 1985 that all four No. 1 seeds and all four No. 2 seeds made the Sweet 16. In those four seasons — 1989, 1995, 2009 and 2019 — we saw an average of five top-two seeds in the Elite Eight and 2.5 in the Final Four, and a No. 1 seed won the championship in three of the four tournaments.

3) The expected Sweet 16 matchup in each quadrant is a No. 1 seed versus a No. 4 or No. 5 seed, and this year we have four such matchups. Historically, No. 1 seeds are 89-29 in those matchups, winning 75% of the time.

Even though we've seen four upsets in these matchups over the last two years, No. 1 seeds remain 19-5 against No. 4s and 5s since 2015, up from the historical rate. They've been especially good against No. 5 seeds in that stretch at 18-3. History expects three of the four No. 1 seeds to win in the Sweet 16.

4) In the modern tournament, No. 1 seeds facing a non-power conference opponent in the Sweet 16 are 44-8 all-time, winning 86% of the time. You may not think Gonzaga or San Diego State count as mid-majors anymore, but history is not on either team's side.

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5) The expected Sweet 16 matchup on the other side of each quadrant is a No. 2 seed versus a No. 3 seed. We have two such matchups this year. You might expect these matchups to be close to coin flips, but that's not actually the case. No. 2 seeds are 36-22 in this matchup, winning almost two out of every three times (62%). In fact, these games often aren't particularly close — nine of the last 13 matchups have been won by double digits.

6) As you might imagine, No. 2 seeds have been dominant against 11 seeds. They've won 16 of 19 such matchups (84%), though nine of the 19 have either been upsets or within four points. Weirdly enough, of the last 12 No. 2 seeds to luck into an 11-seed opponent, only four made the Final Four and none of them went on to win it all.

Good news or bad news for Marquette? You decide.

If NC State does survive, note that No. 11 seeds are 4-4 in the Elite Eight, with all four wins against No. 1 seeds.

7) Our final Sweet 16 matchup this year features No. 2 seed Arizona against No. 6 seed Clemson. The No. 2 seed has dominated this matchup at 23-6 all-time (79%), winning 21 of the last 23. Be careful betting ATS, though — 11 of the last 19 No. 6 seeds have won, taken it to overtime, or lost by one possession.

If Clemson does survive Arizona, note that the Tigers already beat both UNC and Alabama this season.

8) UConn is the defending champion and No. 1 overall seed. Only one of the last nine overall No. 1 seeds made the Final Four, and it's been 11 years since one won the title. The No. 1 overall seed has made 11 of 18 Elite Eights (61%), eight Final Fours (44%) and three title games (17%). The last national champion to go back-to-back was Florida in 2007 — since then, none of them even advanced past the Sweet 16.

Ranking the Remaining Sweet 16 Teams

9) San Diego State is the last team standing from the Mountain West. The MWC has only two upset wins by seed since 2007 and has only advanced past the Sweet 16 once ever in conference history. The Aztecs were responsible for both of those marks when they upset No. 1 overall seed Alabama one year ago as a No. 5 seed in exactly this scenario.

10) Iowa State was unranked in the preseason AP Poll. Not one of the 36 top-two seeds that started the season unranked in the AP poll but finished in the top 10 went on to make the Final Four. Actually, 15 of 23 No. 2 seeds like that lost on opening weekend, so the Cyclones have already exceeded those expectations.

11) This is only the fifth time since 1987 that Duke has been a No. 4 seed or worse, with those teams advancing to now three Sweet 16s, but never further. Once Duke became all-caps DUKE in the early 90s, history says it has either been a No. 1 seed or not good enough.

12) As a top-three seed, Purdue has fallen short of seed expectations in 11 of 12 appearances with losses to Nos. 6, 8, 10, 11, 15 and 16 seeds. Matt Painter is 1-5 ATS and SU in the Sweet 16, and the Boilermakers have as many consecutive tournament upset losses to seeds 13 or worse (3) as all-time Elite Eight appearances. But they're also 7-0 this year against teams still in the field, including wins against Gonzaga, Tennessee and Marquette, possibly their next three opponents.

Gonzaga has tied a record with a ninth consecutive Sweet 16 berth. Mark Few is now 34-11 the first two rounds of the NCAA Tournament but just 9-12 after that.

13) Tennessee has been a top-four seed eight times and has been upset every time without a single Elite Eight berth. Rick Barnes is now 10-22 ATS lifetime in the NCAA Tournament (31%), covering just four of his last 20 games since 2009. That includes 9-18 ATS as a seed favorite (33%) and 6-20 ATS as anything other than a seed favorite of at least 10 (23%), covering just one of his last 16 games.

Creighton has one win against an opponent better than a No. 8 seed since 2002. That came last year in an upset win over No. 3 seed Baylor, the first-ever Creighton win over a top-four seed.

14) The most common Elite Eight matchup features a No. 1 seed versus a No. 2 or No. 3 seed — but history says those matchups are far from equal. No. 1 seeds are fairly dominant at 22-14 against No. 3 seeds, winning 14 of the last 17 matchups with 11 of those wins by at least seven points. But No. 2 seeds actually have a slight edge over No. 1 seeds in the Elite Eight at 24-23 all-time.

15) If a No. 1 seed goes down in the Sweet 16, we'll likely get a No. 4 or No. 5 seed against a No. 2 or No. 3 seed in the Elite Eight. You probably assume the better seed is the favorite there, but history says the exact opposite.

The favored seed is just 8-13 in such matchups (38%). Nine of the last 12 No. 2 seeds have lost in that spot, and the last three No. 3 seed favorites lost by 16, 20, and 28. History says that once a team beats a No. 1 seed, it effectively acts as the No. 1 seed itself going forward.

16) In 15 of the last 17 Final Fours, the lowest seed to arrive did not win another game. Seeding still matters, even at the Final Four. In fact, 12 of the last 16 champs were No. 1 seeds, and two of the other champions were the best seed left in that Final Four. No. 1 seeds are now 40-15 against non-No. 1 seeds on Final Four weekend (73%), and they've won 23 of the last 26 games.