With 10:39 left in a second-round game Sunday, Mike Krzyzewski did something you don’t think of Mike Krzyzewski doing against a No. 9 seed in the NCAA Tournament. No. 1 Duke was more talented and more established than Central Florida. The Blue Devils started four top-15 freshmen, all future pros, led by the star of this college basketball season, Zion Williamson. And yet, locked in a 54-54 tie far earlier in this tournament than anticipated — FiveThirtyEight’s model gave Duke a 91 percent chance of winning before the game — Krzyzewski needed a spark. He called for the Blue Devils to play some zone defense.

It started on a baseline out-of-bounds play for UCF. “Duke is in a zone — no, a matchup, a matchup zone,” Grant Hill called out on the CBS telecast. “They did this one trip against Virginia Tech,” Bill Raftery recalled. Guards Tre Jones and Jordan Goldwire made up the front line of the 2-3 zone. Williamson stood in the paint. Out of that baseline play, UCF drilled a go-ahead 3-pointer. But the zone was enough for Duke to hold off Johnny Dawkins’ team for a while, even if it took a last-minute Duke put-back and a last-second missed UCF tip-in to seal the win.

In all, Duke deployed the zone for 11 possessions, more than in all but three of its games this season. The key second-half stretch lasted eight possessions, of which UCF scored on only three. Mostly, the zone stunted UCF’s rhythm, forcing five 3-point attempts and often pushing the Knights to the end of the shot clock.

The fact that Duke needed a late defensive adjustment at all was a surprise. But a team in its position going to zone was not — it has become a popular strategy in the NCAA men’s tournament, where even brief momentum swings can change games and seasons. Coaches tend to be more apt to use their full playbook to gain an edge. And opponents sometimes have less than 48 hours to prepare for new defensive looks. In other words, the zone can function like an off-speed pitch for opposing offenses who didn’t expect to see it coming.

This season, 12 tournament teams played zone on more than 15 percent of defensive possessions entering the Big Dance, according to Synergy Sports. But 19 teams have played zone on more than 15 percent of their defensive possessions in the tournament .

Teams are going zone in the big dance Among the final 32 teams in the men’s NCAA tournament, the rate of zone used in the regular season vs. the tournament in rounds 1 and 2. Regular Season Tournament Team Zone Plays % Zone Zone Plays % Zone Diff. Iowa 671 32.2% 81 60.0% +27.8 Maryland 30 1.5 34 23.6 +22.1 Oregon 887 48.6 98 69.5 +20.9 UC Irvine 188 8.7 35 27.1 +18.4 Florida 169 8.5 24 18.0 +9.5 Duke 105 4.8 17 13.0 +8.2 Oklahoma 180 8.6 20 15.3 +6.7 Auburn 160 7.7 16 11.9 +4.2 UCF 315 15.8 24 17.9 +2.1 Murray State 87 4.4 9 6.2 +1.8 Virginia Tech 25 1.3 3 2.3 +1.0 Kansas 58 2.7 4 3.2 +0.5 Ohio State 81 4.0 5 4.1 +0.1 Liberty 15 0.8 1 0.8 +0.0 Houston 3 0.1 0 0.0 -0.1 Buffalo 5 0.2 0 0.0 -0.2 Michigan State 5 0.2 0 0.0 -0.2 Purdue 3 0.2 0 0.0 -0.2 Michigan 9 0.4 0 0.0 -0.4 Virginia 11 0.6 0 0.0 -0.6 Villanova 170 8.9 10 8.1 -0.8 Kentucky 22 1.1 0 0.0 -1.1 Minnesota 48 2.3 1 0.8 -1.5 Wofford 65 3.3 1 0.8 -2.5 North Carolina 81 3.6 1 0.8 -2.8 Gonzaga 80 3.6 1 0.7 -2.9 LSU 67 3.1 0 0.0 -3.1 Texas Tech 175 8.6 7 5.4 -3.2 Washington 2018 95.4 133 91.7 -3.7 Florida State 119 6.0 1 0.8 -5.2 Tennessee 195 9.1 2 1.5 -7.6 Baylor 846 41.0 29 22.1 -18.9 Source: Synergy Sports

There was a time when the thought of a Krzyzewski team using a zone was unthinkable. From the 2009-2010 season until 2013-14, Duke played zone on 1.62 percent of defensive possessions. Known as an unusual defense used to compensate for a gap in talent, the zone was often unnecessary for the most athletic teams in the country (read: Duke)

But Krzyzewski has changed over time, employing zone on 14.3 percent of possessions in 2014-15, then 23.5 percent the next year. Last season, Duke played zone on about half of its possessions, including 92.2 percent from Feb. 11 on, throwing off basketball fans everywhere.

This year, with a new batch of freshmen in tow, the Blue Devils have shifted way back to 4.91 percent. But they still break out the zone in a pinch — a 2-3 half-court set or a full-court zone press — which is more than they could say five years ago. A Washington Post story earlier this month described how Krzyzewski learned parts of the 2-3 zone from the master of it, Syracuse coach Jim Boeheim, when Krzyzewski became the head coach of the U.S. men’s national team. Boeheim told The Post he sees hints of Syracuse’s zone in Duke’s defenses today. “I don’t think Coach K should be allowed to play zone,” Boeheim joked to reporters last season.

Zone defense appealed to teams big and small in the tournament’s first weekend. Some were double-digit seeds like Iona, Colgate and Gardner-Webb who needed the zone to try to level the playing field against more athletic teams. But there was also Maryland, which played as many possessions of zone Sunday against LSU (34) as it had all season until that point.

Maryland head coach Mark Turgeon has not used much zone during his eight seasons in College Park — only on 2.7 percent of possessions. But after his technical foul put the Terrapins behind 46-31 with 16 minutes left, he called for a 3-2 zone that baffled LSU the rest of the way. Maryland averaged .95 points allowed on 38 man-to-man possessions and .59 points allowed on 34 zone possessions, erasing the 15-point deficit before losing on a go-ahead layup with less than two seconds left.

Turgeon’s strategy tweak was stat-driven. He knew LSU was one of the worst 3-point shooting teams in the tournament at around 32 percent. “That’s low,” Turgeon told reporters after the loss. “So everything told us to guard that way. We weren’t going to guard Belmont that way, obviously. And so we told the guys yesterday morning when they woke up, we’re going to zone, don’t know when, but we’re going to zone.”

Added LSU interim coach Tony Benford: “We knew they were going to run the 3-2, and we had worked on it. But when you don’t have but one day to prepare, it’s tough.”

In the first round on Friday, UC Irvine turned to its zone defense to fluster Kansas State and earn the tournament’s biggest upset by seed. “We knew they’d play zone, and I was just hoping, I told them to attack with confidence, not to act like we’ve never been there, because we’ve played against a bunch of people, bunch of zones,” Kansas State coach Bruce Weber said after the game. “But obviously we just didn’t get enough.”

The worst 3-point shooting team left in the tournament is Duke at 30.7 percent, a troublesome mark because a good zone defense could force the team to take threes. UCF stayed in Sunday’s game by mixing in a zone at times. That might hint at a blueprint for a team to take down the tournament’s No. 1 overall seed — that is, if that team can figure out Duke’s zone first.

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