College basketball season started on Friday, but the ESPN Tip-Off Marathon culminating in the Champions Classic on Tuesday night is a sign that the season is truly here. Ardent college basketball fans have had this date circled on their calendars for months, as three of last year’s Final Four teams are in action at the United Center.

Duke takes on Kentucky at 7:30 p.m. ET, while Kansas will battle Michigan State at 10. Here are five key matchups to keep an eye on during tonight’s showdowns.

Brandon Ingram vs. whomever Kentucky decides to have guard him

 
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Derek Willis has been a pleasant surprise early for Kentucky, and at 6’9”, he could start off the game checking Duke super freshman Brandon Ingram. Just a few weeks ago, that seemed like a far-fetched scenario when looking ahead to this game. Now, it looks imminent.

Willis is a junior, and in his first two seasons in Lexington, he logged a total of 116 minutes. He’s already scored as many points this season (25) as he did all of last season. But the lanky junior dropped 14 in UK’s season opener against Albany, and he’s played his way into the starting lineup.

Willis is long, has some lateral quickness and has canned five of his nine 3-point attempts this season. But does he have the jets to stay with Ingram? That’s a tough ask. If Willis starts on Ingram, look for Mike Krzyzewski to run him through a plethora of ball screens to see if he really has the defensive chops to stick Duke’s polished wing.

If he can’t, Kentucky might be in some trouble. John Calipari could use a three-guard backcourt of Tyler Ulis, Jamal Murray and Isaiah Briscoe plenty this season. But if Duke trots out its large front line of Ingram, Amile Jefferson and Marshall Plumlee, UK’s small backcourt might not fly.

Murray gives up four inches to Ingram, but on the flip side, the Ulis/Murray/Briscoe combo is likely Kentucky’s most dynamic offensive lineup. It’s going to be interesting to see how Coach K and Calipari manipulate these chess pieces throughout the game.

Grayson Allen vs. Jamal Murray

Jamal Murray throws down a thunderous slam against Albany.
Mark Zerof | USA TODAY Sports Images
Jamal Murray throws down a thunderous slam against Albany.

Grayson Allen hasn’t just picked up from where he left off in last season’s Final Four -- he’s flat out been better. It’s only been two games, but Allen is in the 50/40/90 club (field-goal percentage, 3-point percentage and free-throw percentage) as of now. That’s Stephen Curry-esque.

That probably won’t continue against stiffer competition, which Kentucky represents. Expect to see Murray and Briscoe on Allen for most of the game, and maybe even a dash of Ulis to switch things up.

Murray is a very talented offensive player in his own right, and he and Allen will likely have trouble stopping one another. Expect to see plenty of Murray/Skal Labissiere pick-and-rolls, and if Kentucky can force Duke to switch, we’ll see if the 7’0” Labissiere can make a shorter defender pay despite his slender frame.

A (not so) bold prediction: Murray and Allen will be Kentucky and Duke’s leading scorers tonight, respectively.

Mike Krzyzewski vs. John Calipari

Duke won a national title last season playing small, with Justise Winslow serving as the Blue Devils’ de facto power forward. Winslow was able to bang with opposing bigs, and his offensive versatility gave Duke pristine spacing.

Meanwhile, Kentucky started last season 38-0 using three traditional big men in the starting lineup.

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This season, each team’s roster is entirely different, and the styles of play may be flipped. Duke starts no player shorter than 6’5”, but will Ingram punish smaller defenders enough for Coach K to stay with that lineup instead of ditching it for small-ball? Can Ingram hang with Marcus Lee or Labissiere if he’s asked to play power forward? His defensive versatility is a huge X-factor for this team, and look for Calipari to test him early on to see if he’s exploitable.

For Kentucky, we’ll see how daring Calipari is in using Ulis, Murray and Briscoe at the same time when Duke has its big-ball lineup on the floor. One coach is eventually going to have to crack; it’s going to be fascinating to see who does first.

Denzel Valentine vs. Wayne Selden

Denzel Valentine is one of the most complete players in the country.
Mike Carter | USA TODAY Sports Images
Denzel Valentine is one of the most complete players in the country.

Switching gears to the Michigan State vs. Kansas matchup, the Jayhawks do not have an obvious candidate to stop Valentine. In fact, by the numbers, Selden was Kansas’ worst defender last season (103.7 defensive rating, last among KU regulars). Yet at 6’5”, 230 with a 6’10” wingspan, he’s the guy on Kansas that has the most ideal physical profile to slow down Valentine.

Bill Self starts two point guards in Devonte’ Graham and Frank Mason, so at tip-off, Selden is going to defend Valentine. Depending on how the game progresses, Brannen Greene (5-for-5 from 3 in the Jayhawks’ opening game) may see some time on the Michigan State star, as could the uber-athletic Sviatoslav Mykhailiuk.

Self’s defensive game plan is going to be a huge factor in the type of game Valentine has. No. 45 in green and white is a facilitator at heart, and the Spartans have knock-down shooters in Bryn Forbes and Eron Harris to surround him. Help too much to contain Valentine drives, and those dudes will burn you.

The one perimeter player Kansas can afford to sag off is Lourawls Nairn Jr., who shot 31.8 percent from the floor last season. Perhaps Self will have either Mason or Graham play free safety in hopes to contain Valentine and the shooters, but who knows? It’s an intriguing subplot going into tonight.

Michigan State freshmen vs. Kansas freshmen

These are two veteran-laden teams, but freshmen on both sides have flashed signs of brilliance early on.

Spartans big man Deyonta Davis had 13 points, 11 rebounds and five blocks in just 21 minutes of action in MSU’s first win against Florida Atlantic. With Gavin Schilling missing tonight’s game and Matt Costello serving as more of an offensive hub than a defensive enforcer, Davis might be Tom Izzo’s best option to guard Perry Ellis.

For Kansas, Carlton Bragg could have a major impact on tonight’s game.  Jamari Traylor is a very solid starter for the Jays, but Bragg has on offensive skillset that Traylor can’t match. If he can hold his own on the defensive end of the floor, Bragg could dip into Traylor’s minutes and provide Kansas with another interior presence to complement Ellis.

Let the games begin.