Isaiah Thomas will prove to be a handful for UNC on Sunday. (Shotgun Spratling)

From a controversial, you-have-to-see-it-to-believe-it ending, to a double OT thriller, to a trio of spectacular guard performances from Jimmer Fredette, Kemba Walker and Jacob Pullen, the day was not short on drama.

Though it may be difficult for Sunday to compare, the one thing this tournament has taught us is to expect the unexpected.

Here are two games to keep an eye on:

Game most likely to result in an upset: Washington-North Carolina

This matchup pitting two of the hottest teams in college basketball may end up resembling a track meet more than a basketball game. Washington entered the tournament third in the country in points per game and North Carolina is coming off a 102-point performance in its opening round game.

Though the Tar Heels have a definite size advantage in the frontcourt, they will need to play stellar perimeter defense and find a way to limit the effectiveness of Isaiah Thomas, Washington’s electric point guard. The Huskies also have a bevy of capable outside shooters. When they get hot, the Pac-10 champions can be difficult to beat.

Carolina got a whopping 84 points in their first game from the three-headed monster of Harrison Barnes, Tyler Zeller and John Henson. As outstanding as those three have been, they must stay out of foul trouble because UNC has a relatively short bench.

In order for Washington to pull off the upset, they will need to overcome a highly partisan Charlotte crowd.

Game most likely to end on a buzzer-beater: Texas-Arizona

Both these teams survived upset bids in the first round and are very evenly matched on paper, down to their identical 28-7 records. An interesting matchup will be the post battle between Derrick Williams and Tristan Thompson. Williams has had his way all season long, showing an ability to score and rebound at a high level as well as a penchant for timely blocked shots.

However, Thompson is a very agile big man who has shown he is capable of outplaying elite NBA prospects, as he did in the Longhorns’ first game against Keith Benson of Oakland. Jordan Hamilton, Texas’ leading scorer and a former AAU teammate of Williams’, has a complete offensive game and is part of a deep backcourt.

‘Zona doesn’t have any real stars outside of Williams, but it does have a lot of solid role players and excellent depth, with nine players seeing over 10 minutes of action per game.

Gus Johnson isn’t broadcasting this game, but if it lives up to expectations it’s liable to induce incoherent screams from even Marv Albert.

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To reach Johnie Freatman by email, click here. Follow him on Twitter, @scfreats.