No. 4 Butler (25-8) vs. No. 1 North Carolina (29-7)
Bottom line: Butler is 2-4 against No. 1 seeds in the NCAA Tournament all time, reaching the national title game in 2010 and 2011 when they knocked off a No. 1 seed. The Bulldogs also beat defending national champion Villanova not once, but twice this season. They have not trailed in beating a pair of double-digit seeds, Winthrop and Middle Tennessee. The last time North Carolina came into Memphis, Tenn., as the South’s No. 1 seed, the Tar Heels wound up winning the 2009 national championship. The Atlantic Coast Conference regular-season champs routed Texas Southern and rallied from five down in the final 2:57 to beat Arkansas and reach this stage. Holtmann vs. Williams: Butler has won the last two meetings of these teams, and Bulldogs coach Chris Holtmann is 1-1 himself with a win in 2014 at the Battle 4 Atlantis. Veteran coach Roy Williams is 7-1 in the Sweet 16 with North Carolina. Keep an eye on: Butler’s Andre Woodson and North Carolina’s Justin Jackson. Woodson played his last two seasons at the University of Memphis before graduating and transferring to Butler. He is 8-of-14 behind the arc in the tournament and returning to an arena where he averaged 38 percent shooting from 3-point range. Jackson, the ACC player of the year, is averaging 18.1 points per game and has hit a school-record 98 3s this season. Did you know? Williams has made it to the NCAA Tournament in 27 of his 29 years as a head coach. This is his 18th berth in the Sweet 16, where he is 12-5 overall.