WINSLOW — Ask anyone how to beat the Waterville girls, and they’ll all say you need to slow down Colleen O’Donnell.

In Tuesday night’s Eastern B preliminary round game, Winslow couldn’t slow O’Donnell down. But the Black Raiders also couldn’t make a run when O’Donnell was on the bench with foul trouble. That and Waterville’s composure down the stretch led the 13th-seeded Purple Panthers to a 42-34 upset victory.

“Two years ago, seven kids (in the program),” Waterville coach Rob Rodrigue said. “Fifteen, 18 kids now. Our goal was to get a prelim, so we’re kind of playing house’s money right now.”

Waterville (11-8) will now play No. 5 Foxcroft at 1:35 p.m., Saturday, at the Cross Insurance Center in Bangor. Winslow had beaten the Panthers twice this season, by 26 and nine points. O’Donnell scored 20 points for Waterville on Tuesday, while Hannah Allen added 12, and Jordan Jabar was 10 of 14 from the line for 10 points.

Winslow, the fourth seed, finishes at 14-5. Last season, the Black Raiders were the No. 13 seed, and upset Gardiner in the prelims to advance to Bangor.

“We could sit here until we’re blue in the face and think what went wrong in the game,” Winslow coach Lindsey Welch said. “But when it came down to it, they outworked us, and we missed a couple shots that we probably should have made. That’s the difference, right there.”

Two of the biggest shots of the game came in the first three minutes. O’Donnell is devastating when she drives to the basket, so the Winslow defenders gave her some space at the start of the game. But O’Donnell’s first two shots were a long jumper from the left corner and a 3-pointer from the right wing. She made both, and Winslow had to respect her outside shot the rest of the night.

“Colleen’s really developed into a good shooter,” Rodrigue said. “I’ve had her for three years now, and I’ve asked her for three years to shoot the ball. So when she came out tonight and let it fly, I was happy.”

“We knew that she could hit 3s, but we wanted her to prove herself first,” Welch said. “Much respect to her. Her and Allen just kind of put that team on their shoulders. They weren’t going to lose their last game. We had to make that adjustment at halftime, especially, and make sure that we were a little bit closer. Getting a little bit closer means she can go by us with that extra step. She’s a tough matchup for anybody.”

The Panthers took only eight field goals in the first half, while Winslow was 3 for 17 and missed about five layups. Waterville led 19-15 at halftime.

“I like the way we responded to their physicalness,” Rodrigue said. “When they beat us at our place, they came out the second half and kind of really physicaled us up, and gave us a real hard time with that.”

Led by Devin Fitzgibbons (seven of her 12 points in the third quarter), Winslow went ahead 23-20 early in the third quarter. When O’Donnell picked up her fourth foul with 2:50 to go in the quarter, the score was 23-23. She stayed out until the 5:02 mark of the fourth quarter, and when she returned it was 31-31. The key play for Waterville in that stretch was Allen draining a 3 as Winslow committed a foul, followed by Jabar making both ends of the one-and-one. That turned a 29-25 deficit into a 30-29 Waterville lead.

“I think in the beginning of the year, we were a little more relying on Colleen,” Rodrigue said. “Those kids stepped up and did a nice job. Katie Thompson and Kaitlyn Spaulding really came in and gave us some big minutes.”

O’Donnell gave Waterville the lead for good at 34-32 when she drove baseline past two defenders for a layup. After Winslow turned the ball over, Jabar made two free throws. With under two minutes remaining, the Panthers went into a stall, and O’Donnell saw an opening and weaved for a back-breaking layup to make it 38-32 with 1:23 to play.

“We knew what to expect, and we prepared for it,” O’Donnell said. “I think we just played our best, and we knew we could play like that.”

For Winslow, the end before Bangor was unexpected. The Raiders won 14 games with only 12 players in the program, and will not lose anyone to graduation.

“There was a positive from the game, and I was trying to search for it for the 10 minutes before going in that locker room,” Welch said. “We don’t have a senior. We have the whole team back, and I’m really excited to see what they do in the offseason.”

Matt DiFilippo — 861-9243 mdifilippo@centralmaine.com Twitter: @Matt_DiFilippo