The first weekend of the 2019 NCAA Tournament is in the books, and the field has dropped from 68 teams down to 16. All of the No. 1, No. 2 and No. 3 seeds advanced, mixed in with two No. 4 seeds, a No. 5 seed and No. 12 seed Oregon.

The headliner game in this year's Sweet 16 will be the rematch between No. 1 seed Duke and No. 4 seed Virginia Tech in the East Region semifinal. Virginia Tech defeated Duke 77-72 when the two played in late February but the Blue Devils were without Zion Williamson in that game. Duke is coming off of a thrilling one-point win over No. 9 seed UCF in the second round.

Let's now take a closer look at the matchups ahead, with the Sweet 16 field now set. 

West Region

No. 4 Florida State vs. No. 1 Gonzaga

Leonard Hamilton takes his team to the Sweet 16 for the second consecutive year. This FSU team has a lot of length including Terance Mann and 7-foot-4 center Christ Koumadje. Sophomore Mfiondu Kabengele provides a spark of the bench, leading the team in scoring.

Gonzaga is the only team in the country to beat a full-strength Duke team this season. The Zags are one of the most efficient shooting teams in the country, and also sport one of the most efficient players in the nation: Brandon Clarke. The transfer from San Jose State is shooting almost 70 percent from the field, and is one of the best shot blockers in the nation. Forward Rui Hachimura won West Coast Player of the Year and is dynamic near the rim.

No. 3 Texas Tech vs. No. 2 Michigan

Texas Tech has a little bit of everything on its team. Tariq Owens is one of the best shot blockers in the country. Jarrett Culver is a big guard who averages over 18 points per game and will likely be a lottery pick. Davide Moretti is the only player in college basketball to shoot 50 percent from the field, 40 percent from 3 and 90 percent from the free throw line. The Red Raiders are also stingy on defense, ranking in the top five in defensive field goal percentage and scoring defense.

Michigan plays its best defense near the perimeter. The Wolverines led the Big Ten in 3-point field goal percentage defense, allowing opponents to connect on only 29 percent of its 3s. Zavier Simpson has been assisting at an elite rate as of late, totaling nine or more assists in his last five games and eight of his last 10. Ignas Brazdeikis, the Big Ten Freshman of the Year, is leading the team in scoring with almost 15 points a game and shooting over 40 percent from 3.

South Region

No. 3 Purdue vs. No. 2 Tennessee

  • When: Thursday at 7:29 p.m. ET
  • Where: KFC Yum! Center in Louisville, Ky.
  • TV: TBS
  • Live streamMarch Madness Live

The Boilermakers advance to the Sweet 16 for the third year in a row, but their last two seasons have ended in the round and the program has not reached the Elite Eight since 2000. Matt Haarms is contributing on the offensive end more than ever; the 7-foot-3 center has taken 12 shots in two of the team's last three games (and made eight in each). He never attempted double-digit field goals in a game prior. Also, leading-scorer Carsen Edwards is coming off a game where he made nine 3-pointers.

Tennessee is one of three teams left in the field that is ranked in both the top 20 in field goal percentage and defensive field goal percentage. This team takes high-quality shots and forces opposing teams to hoist bad ones. This Tennessee team is battle-tested and led by veterans. Its top six scorers have all been in the program for at least three years. Grant Williams won SEC Player of the Year for the second consecutive season -- the first player in the conference to achieve that feat in 24 years.

No. 12 Oregon vs. No. 1 Virginia

  • When: Thursday at 9:59 p.m. ET
  • Where: KFC Yum! Center in Louisville, Ky.
  • TV: TBS
  • Live streamMarch Madness Live

The Ducks have rattled off 10 wins in a row thanks to tremendous defense. In that span, they have allowed only 54.2 points per game and won by an average of 17.9 points per game. Payton Pritchard and Louis King have helped turned around what recently looked like a failed season into a third Sweet 16 trip in four years.

Virginia has a reputation of being one of the best defensive teams in the country, and this year's squad is no different. This team -- led by Kyle Guy, De'Andre Hunter and Ty Jerome -- is ranked No. 1 in scoring defense this season. Tony Bennett's team also does not have too many mental errors; the Cavs are among the best in the nation in turnovers and fouls per game.

East Region

No. 3 LSU vs. No. 2 Michigan State

LSU won the SEC with a 16-2 record, its most conference wins since 1981. But the team is now without coach Will Wade, who is suspended indefinitely for his alleged involvement with the pay-for-play scandal, with ex-North Texas coach Tony Benford currently serving as the interim head coach. The Tigers have a high-octane offense, averaging over 80 points per game and have a very balanced offense, with four players averaging in double-figure scoring: Tremont Waters, Naz Reid, Skylar Mays and Javonte Smart.

Since suffering a three-game losing streak in February, the Spartans rattled off wins in seven of its last eight regular seasons games. Then they won the Big Ten tournament with an average margin of victory of eight points. Tom Izzo's squad is led by junior guard Cassius Winston, who can put up 20 points on any given night and is one of the best passers in the country.

No. 4 Virginia Tech vs. No. 1 Duke

Virginia Tech does not have a lot of height on its roster, and it shows in its rebounding. The Hokies are ranked in the 300s in rebounds per game and do not block a lot of shots. But what Virginia Tech does do well is shoot the ball. It is incredibly efficient on both 2 and 3-pointers. Ty Outlaw is a 3-point specialist, shooting around 80 percent of his shots from that range. Nickeil Alexander-Walker, the team's leading scorer, has been a workhorse, averaging 39 minutes per game since Feb. 18.

The Blue Devils narrowly escaped UCF in the second round with a one-point win, but in the final two minutes, Duke showed why it is one of the best teams in the country: Zion Williamson and RJ Barrett. The pair scored 11 of the team's final 13 points to keep the team's hopes alive. Duke is the only team in the country to have two players averaging over 22 points per game.

Midwest Region

No. 5 Auburn vs. No. 1 UNC

  • When: Friday at 7:29 p.m. ET
  • Where: Sprint Center in Kansas City, Mo.
  • TV: TBS
  • Live streamMarch Madness Live

Two things are going to keep the Tigers advancing: 3-point shooting and turnovers. Auburn has taken the second most 3-pointers in the country and is third in turnover margin. This is what it did in the first two rounds of the tournament, shooting 25 of 61 from 3-point land and forcing 32 turnovers, compared to the 16 it committed. Bryce Brown and Jared Harper both have the ability to heat up at any points and change the game.

This UNC team has a unique blend of veteran presence and youth. Senior Cameron Johnson led the ACC in 3-point percentage and Luke Maye averaged a double-double for the second consecutive season. Kenny Williams and Maye have already been a part of two teams who have made the national championship. Freshman Coby White has been an unbelievable replacement for Joel Berry II, emerging as one of just two freshmen in the country averaging over 16 points and four assists per game (RJ Barrett).

No. 3 Houston vs. No. 2 Kentucky

  • When: Friday at 9:59 p.m. ET
  • Where: Sprint Center in Kansas City, Mo.
  • TV: TBS
  • Live streamMarch Madness Live

Kelvin Sampson brings Houston to the Sweet 16 for the first time since 1984. The Cougars were one of four teams to come into the tournament with only three losses. Senior Corey Davis Jr. is the leading scorer and has scored 20-plus points in both NCAA Tournament games. Houston is a top-10 defense in the country and very good at creating second-chance opportunities on the offensive end.

For only the second time in 10 years, UK's leading scorer is not a freshman. Sophomore P.J. Washington leads the team with almost 15 points a contest while shooting over 50 percent from the field and just under 42 percent from 3. Of course, Kentucky also has its talented freshman right alongside him. Tyler Herro and Keldon Johnson are both capable of putting up large amounts of points in short periods of time. The Wildcats are also ranked in the top 10 of the country in free throws made.