WEST LAFAYETTE, Ind. — Iowa's defense spent the first half chasing No. 14 Purdue on the perimeter.
When that didn't work, coach Fran McCaffrey turned up the pressure and watched the Boilermakers fall apart Saturday night.
The Hawkeyes allowed only eight second-half baskets, forced 10 turnovers and rallied from a 17-point halftime deficit to rally for a 70-63 upset and Purdue's first home loss of the season.
"We had some success with it last year, more (Saturday)," McCaffrey said of the halfcourt traps he used in the second half.
"Against this team, in particular, because they're so good in halfcourt offense, you've got to try to go get them a little bit."
The Hawkeyes (11-3, 2-0 Big Ten) executed the plan perfectly and managed to pull off an impressive double by sweeping two top 15 teams this week. They beat No. 1 Michigan State on Tuesday and now have four straight wins.
Jarrod Uthoff led the way with 25 points. Peter Jok had 11 points and nine rebounds. But the Hawkeyes won this game purely because of their stifling defense, which forced Purdue (13-2, 1-1) to lose its composure.
"We wanted to be more aggressive with it, which we were," McCaffrey said. "We were a little tighter, more aggressive and more active."
It was a complete reversal from the first half when Purdue made 7 of 14 3-pointers and built a 37-20 lead.
But in the second half, Purdue's shooters went cold and Iowa's usual suspects warmed up with some easy baskets. Iowa was 18-of-28 from the field over the final 20 compared with 7-of-30 in the first half.
NO. 1 MICH. ST. 69, MINNESOTA 61: Bryn Forbes scored 20, making three 3s in the second half to help the visiting Spartans (14-1, 1-1 Big Ten) respond to last week's loss at Iowa. Matt Costello had career highs of 17 points and 15 rebounds for Michigan State four days after it fell 78-63 to the Hawkeyes in its conference opener.
NO. 2 KANSAS 102, NO. 23 BAYLOR 74: Wayne Selden had 24 points, Perry Ellis added 17 and the host Jayhawks (12-1) used a big run over the first 10 minutes to swamp the Bears (10-3) in their Big 12 opener. Kansas charged out to a 22-4 lead then turned back every attempt by Baylor to make it a game.
NO. 3 OKLA. 87, NO. 11 IOWA ST. 83: Buddy Hield scored 22 for the host Sooners (12-0), who matched the second-best start in school history in a Big 12 opener. Oklahoma, the nation's top 3-point shooting team, made only 3 of 16 3s in the first half but was 8-of-13 in the second. Georges Niang scored 29 and Deonte Burton had 14 of his 19 points in the second half for the Cyclones (11-2).
NO. 4 MARYLAND 72, N'WESTERN 59: Melo Trimble scored 24 and Rasheed Sulaimon added 16 for the visiting Terrapins (13-1, 2-0 Big Ten), who took a 40-20 lead on the way to their seventh straight victory.
NO. 5 UVA 77, N. DAME 66: Anthony Gill had seven of his 14 first-half points during a 21-4 run, and the host Cavaliers (12-1) cruised to their 11th straight victory in an ACC opener.
NO. 6 XAVIER 88, NO. 9 BUTLER 69: Remy Abell scored a career-high 21 for the host Musketeers (13-1, 1-1 Big East), who bounced back from their first lost and sent the Bulldogs (11-3, 0-2) to their most lopsided defeat in two seasons.
NO. 7 UNC 86, GA. TECH 78: Joel Berry scored a career-high 19 and hit the go-ahead 3-pointer with 5:07 left to lift the host Tar Heels (13-2, 2-0 ACC), who had fits with the Yellow Jackets all game. Georgia Tech led by nine in the first half by three at halftime and by one with six minutes left before the Heels finally pushed ahead for good.
NO. 10 KENTUCKY 83, OLE MISS 61: Tyler Ulis had 20 points and 10 assists for the host Wildcats (11-2) in their SEC opener. Ulis set the tone for the blowout, scoring seven of Kentucky's first nine as the Wildcats ended the Rebels' seven-game winning streak.
NO. 12 PROVIDENCE 83, ST. JOHN'S 65: Kris Dunn had 26 points, nine rebounds and six assists to lead the host Friars (14-1, 2-0 Big East) to their eighth straight win. Dunn scored 12 straight in the second half after the Red Storm closed within 56-50 with 9:30 left.
NO. 13 MIAMI 64, SYRACUSE 51: Sheldon McClellan scored 22, Ja'Quan Newton made two big 3-pointers in the second half and the host Hurricanes (12-1) relied on defense to get past the Orange in their ACC opener. Miami blew it open with a 12-0 run in the final minutes.
NO. 15 DUKE 81, BC 64: Brandon Ingram had 25 points and nine rebounds to lead the visiting the Blue Devils (12-2) in an ACC opener. Grayson Allen had 17 points, nine rebounds and five assists for Duke, which who beat the Eagles for the 10th straight time.
NO. 19 W. VA. 87, KANSAS ST. 83, 2 OT: Jaysean Paige scored 18 of his 25 after halftime, Tarik Phillip hit a floater with 4.5 seconds left in the second overtime and the visiting Mountaineers (12-1) toughed one out in a Big 12 opener.
NO. 20 TEXAS A&M 92, ARKANSAS 69: Senior guard Jalen Jones scored a career-high 28 for the host Aggies (11-2), who capitalized on 15 Razorbacks turnovers and turned them into 22 points in an SEC opener. Senior guard Alex Caruso set the school career record for steals with 230.
NO. 22 CINCINNATI 76, TULSA 57: Farad Cobb had five 3-pointers and finished with 21 points as the host Bearcats (11-4, 1-1 AAC) snapped a two-game losing streak by building a 24-point first-half lead.
NO. 24 S.C. 86, MEMPHIS 76: Sindarius Thornwell scored 18, Michael Carrera had 16 points and 11 rebounds and the host Gamecocks outlasted the physical Tigers to improve to 13-0 and continue their best start in 82 years.
INDIANA 79, NEBRASKA 69: Kevin "Yogi" Ferrell scored 24 and Thomas Bryant added 19 to lead the visiting Hoosiers (12-3, 2-0 Big Ten), who won their seventh straight game.