INDIANAPOLIS -- Nia Coffey scored a season-high 34 points, Lauren Douglas added 17 -- including four free throws in the last 10 seconds -- and ninth-seeded Northwestern edged eighth-seeded Iowa 78-73 in the second round of the Big Ten tournament on Thursday.

Coffey had 15 points in the second quarter as the Wildcats erased a five-point deficit to lead 41-32 at the half. Iowa's Megan Gustafson had 13 of her 27 in the third quarter, including the last five to help the Hawkeyes cut a 12-point deficit to 60-55 entering the fourth quarter.

Back-to-back baskets by Gustafson and Kathleen Doyle put Iowa up 69-68 with 3:45 to play but Christen Inman quickly answered for Northwestern. The Wildcats were clinging to a one-point lead when Ashley Deary made two free throws with 14.8 seconds left. Douglas rebounded an Iowa miss and made two from the line at 6.7 and after a Gustafson layup, Douglas iced it with four seconds to go.

The Wildcats (20-10) face top-seeded and ninth-ranked Ohio State in the quarterfinals on Friday. Coffey, who had the fourth-highest point total in tournament history, and Douglas both had eight rebounds while Deary had nine points, seven assists, five rebounds and four steals.

Iowa (17-13) also got 18 points from Ally Disterhoft.