SIOUX CITY, Iowa -- Unfortunately for Indiana Wesleyan University Pool F at the 2012 NAIA Volleyball National Championship has been flipped upside down.

No. 7-ranked Indiana Wesleyan joins No. 6-ranked The Master's (Calif.) College as the top two teams in Pool F and both were upset in their first match of the national tournament. Indiana Wesleyan lost the tournament opener to No. 21-ranked Viterbo (Wis.) University 3-1 by scores of 27-25, 23-25, 20-25, 21-25.

No. 20-ranked Cal State-San Marcos upset The Master's earlier in the evening as the top two seeds were beaten by the bottom two seeds.

The opening day loss puts Indiana Wesleyan in must-win mode on Wednesday and Thursday for their best chance to advance out of pool play and into the tournament bracket. The top two teams in the four team bracket will continue national tournament play on Friday.

A big factor on Tuesday was unforced errors, particularly on serves. Indiana Wesleyan committed 10 service errors in the loss while Viterbo had just one.

Four Wildcats tallied double-digit kills, led by senior outside hitter Rachel Quackenbush with 14. Sophomore opposite hitter Alijah Mulitauopele added 12 kills while junior outside hitter Rae Brandes and freshman middle hitter Kristin Predajna each added 11. Senior setter Yui Iwase assisted on 48 of the Wildcat kills.

Defensively, junior libero Rebecca Brandes earned a team-best 27 digs while Rae Brandes added 18. Iwase finished with 13 digs while senior defensive specialist Jordan Sudzina added 12 and Quackenbush had 11.  IWU finished with six blocks and were led at the net by junior middle hitter Kristine Egebrecht. She had one solo block and four block assists.

Indiana Wesleyan (35-3) returns for their second pool play match on Wednesday against Cal State-San Marcos. The match will begin at approximately 9 p.m. ET. Viterbo (33-7) battles The Master's in the other Pool F match on Wednesday.