WEST LAFAYETTE, Ind. (AP) -- Illinois coach Theresa Grentz is looking for answers. Purdue coach Kristy Curry thinks she's found some.

	Illinois' Tauja Catchings, right, knocks the ball away from Purdue's Katie Douglas.

"I don't know what it is," Grentz said after her Illini (No. 12 ESPN/USA Today, No. 13 Associated Press) had their lowest point production of the season Thursday night in a 73-55 loss to No. 19 Purdue. "I just don't understand it and I don't have any answers. We'll go back to practice and work ... That's all."

Curry and her players credited defense for the Illini's third consecutive loss.

"The difference was we tried to start on the defensive end, to focus on that and we got some stops to trigger our offense," said Big Ten scoring leader Katie Douglas, who led all scorers with 22 points.

"That was our focus to come out and play hard defense. Our defense converts to our offense," said Kelly Komara, who hit four 3-pointers and contributed 18 points.

"They really struggled outside against Michigan and they got beat with Michigan playing a zone, so we took that to heart and we came out and played a tough zone defense against them."

Purdue (11-5, 3-3 Big Ten) has won 23 of its last 25 against Illinois (14-7, 4-3), which hasn't won here since 1984.

"We realized tonight how good we can be. ... how good we are. We need to find that again, and I think it all starts on the defensive end," Curry said. "We played harder, we played smarter, we're playing more together.

The Boilermakers never trailed and took the lead for good at 6-4. Purdue built a 31-21 halftime lead as Illini star Tauja Catchings picked up three quick fouls. Illinois, averaging 78 points a game, shot just 36 percent in the first half (9-of 25) and 40 percent for the game.

Catchings, who fouled out with 15 seconds to play, led Illinois with 19 points and Susan Blauser had 13.

Purdue broke the game open with an 11-4 run to start the second half while the Illini missed their first six shots of the period. Camille Cooper, who finished with 14 points, ignited the run with two field goals and Purdue led 39-23 after a layup by Shinika Parks.

Illinois scored its first points of the second half on two free throws by Kylie Martin and the visitors didn't get their first field goal of the half until Catchings scored with 15:31 to play.

Komara and Douglas each hit two 3-pointers as the defending NCAA champions built a 58-38 lead and the Illini trailed by double figures thereafter.

Purdue had a 38-24 rebounding advantage, with Michelle Duhart getting 10.