In the days leading up to the Sweet 16 showdown between Illinois and Iowa State, much of the buzz centered around the Illini’s top-ranked offense versus the Cyclones’ top-ranked defense. Illinois’ offense brought plenty of fireworks Thursday night, but ultimately, its defense sent it to the Elite Eight. With 23 seconds remaining, standout Illini guard Terrence Shannon Jr. played free safety and intercepted a floating Milan Momcilovic pass in one fluid motion. Shannon zoomed the other way, swiftly slammed it home with 17 seconds left to push the margin to six, and let out a primal scream and salute. He poured in a game-high 29 points, powering No. 3 Illinois past No. 2 Iowa State, 72-69, at TD Garden. Advertisement The Illini (30-7) are onto their first quarterfinal since 2005 after depriving the Cyclones of their first trip since 2000. Illinois will get a crack at defending champion No. 1 UConn in the Elite Eight this Saturday, at 6:09 p.m., back at the Garden. The Huskies dispatched No. 5 San Diego State, 82-52, in a 2023 title game rematch earlier Thursday. Illinois coach Brad Underwood – who ripped off his shirt and soaked his players with a water gun in the locker room – put on his game face as he arrived at the podium at 12:51 a.m. “I’m super excited and proud,” Underwood said. “We didn’t come here to win one game. We came here to win two. To advance to the Elite Eight is special, and we have a great challenge. We’ll dive into them sometime about 3 a.m.” Fans in orange, red, and stragglers in UConn blue formed a rainbow throughout the typically green Garden – turning a pro sports town into a college town in an atmosphere that lived up to the hype. Illinois, playing in front of a particularly enthusiastic crowd, leaned on its depth and experience the entire way. The Illini jumped out to an early 16-6 edge through the opening 10 minutes, suffocating the Cyclones (29-8) with tenacious ball pressure. Advertisement Shannon buried three 3-pointers, blowing a kiss to the Iowa State bench on the first and benefitting from a fortuitous bounce on the third. Coleman Hawkins (12 points) and Ty Rodgers did damage at the rim, bothering ISU with their length and force on both ends. “I think our biggest thing is maintaining that same level of intensity and physicality and then staying true to our principles and forcing tough twos,” Hawkins said. “I think the game plan tonight worked for us.” Iowa State found a rhythm late in the half, leaning heavily on shifty playmaker Curtis Jones (season-high 26 points) and slicing it to 28-20 with 4:14 left on a deep Tamin Lipsey 3-pointer. Illinois led, 36-26, at halftime, thanks in large part to a 16-point
explosion from Shannon. The Cyclones hung around despite
shooting just 29 percent from the floor. Iowa State only turned it over three times and generated a few high-quality looks in transition to stay afloat. Keshon Gilbert (14 points) poured in nine points in the first four minutes of the half, attacking the basket relentlessly and drawing contact at the rim. ISU seized momentum and trimmed the margin to 41-36 with 15:42 remaining. Shannon and Hawkins both picked up their third fouls early in the half, and Shannon his fourth with 11:17 remaining, which forced Underwood to go deep into his bench. Fortunately for Underwood, his second unit is more than capable. Advertisement “I think it’s what we’ve been through all season,” Illinois guard/forward Luke Goode said. “We have a super mature team. I know Coach talks about it all the time. When you get in situations like that, the guys that were on the court basically have seen it all.” After Iowa State trimmed it to 51-49, Illinois big Dain Dainja went to work inside. The Cyclones nearly took their first lead on multiple occasions, but a timely Marcus Domask and-one gave Illinois a 56-51 edge with 5:38 left. Goode added two free throws to make it 66-60 with 1:37 left. Just when it seemed like Iowa State might seize momentum, Illinois provided a counterpunch every single time. “I loved our resiliency, playing through those moments,” Underwood said. Jones delivered inside to make it 67-64 with 56 seconds remaining, then Shannon finished what he started. He added two more clutch free throws with six seconds left after his throwdown, and that was enough to keep dancing. Underwood highlighted Shannon’s competitive nature and ability to stay in the game through foul trouble. He became the first player in program history to score 25 or more points in three straight tournament games. “He’s a really tough cover,” Iowa State coach T.J. Otzelberger said. “He’s as aggressive of an offensive player as there is in the country, and he is playing at such a high level. You can’t let a guy like that get the opportunities that we allowed for him early where he got his confidence going.” Advertisement Trevor Hass can be reached at trevor.hass@globe.com .