St. Ambrose recovered from a slow start to give No. 1 Northwestern (Iowa) all it could handle in the pool play opener for both teams Wednesday morning at the NAIA Championships in Sioux City, Iowa. But ultimately the nation's top-ranked team pulled out a 25-15, 25-22, 24-26, 25-19 win.

The loss, which snapped an eight-match winning streak, forces the Bees into a must-win situation Thursday against No. 18 Bellevue to have any chance to advance into Saturday's quarterfinals.

In its first final-site appearance at Nationals since the 2010 season, SAU was a much different team after dropping the opening set.

The Bees had a three-point lead as late as 14-11 on a Kaleigh Bergschneider ace in the second set. The lead remained two at 15-13 following a Meredith Siebers kill. Four straight points gave Northwestern (28-2) a lead it would not relinquish. Another Siebers kill had the Bees within a single point at 21-20 before the Red Raiders went on a three-point run to regain control. SAU was able to fight off a pair of set points before Northwestern claimed the set 25-22.

St. Ambrose finally broke through in the third.

Behind the serving of Mackenzie Grafton, the Bees jumped quickly in front. Siebers and Alex Horne each had two kills and Grafton and Audrey Witte had one apiece to help the team open up a 7-3 lead. The margin was 19-14 before the Raiders made a run. A 7-2 spurt knotted the set at 21-21. A pair of Meredith Umland kills kept things even at 23-23. Northwestern earned a match point at 24-23 but that was erased on a Raider ball handling error. Hannah Sondag had a big service ace to put the Bees in front 25-24, and Grafton followed with a kill to extend the match.

Momentum quickly returned to Northwestern in the fourth as the Raiders won the first four points. The Bees matched them from there and were as close as 18-16 late, but the Raiders won five of the next six points to build a 23-17 cushion and they closed out the match four points later.

St. Ambrose (20-15) finished with just two fewer kills than Northwestern (56-54). But the Raiders hit at a .278 clip, while the Bees, facing the nation's top-blocking squad, hit .186. The Raiders collected 12 total blocks.

Siebers led all players with 19 kills. She also picked up 13 digs. Umland was credited with 13 kills. Grafton nearly posted a double-double, finishing with nine kills and 12 digs. Horne put down seven kills while Witte and Sondag each had three.

Sondag had a match-best 41 assists to go along with 16 digs. Lexi Huntley picked up 12 digs and Adriana Diaz recorded seven.

SAU will now face Bellevue at 10 a.m. Thursday. Northwestern and Bellevue will play the final match of the pool Friday morning. The pool winner will advance into the quarterfinals.