The Centennial Cougars, seeded No. 2 in the Section 4AAA volleyball tournament, had a first-round bye, then turned back Irondale, 25-17, 25-19, 22-25, 25-16, at home on Thursday evening in the quarterfinals. The Cougars will duel No. 3 Stillwater on Monday at 6 p.m. at North High School in St. Paul. The other semifinal, No.1 North vs. No. 4 Mounds View, will follow. The championship will be held Thursday, 7 p.m.m at a site to be determined.