Major conference races going down to the wire in final week

By JOHN MARSHALL
AP Basketball Writer

An unprecedented day of chaos led to changes nearly everywhere in the AP Top 25, except the top two spots. It also tightened up major conference races across the country. Heading into the final week of the regular season, the first-place team in every undecided league except the Pac-12 has a lead of one game or less. The Pac-12 hasn’t been decided, either. No. 2 Arizona leads No. 16 Southern California by 1 1/2 games, but has three games this week. In the Big East, No. 9 Providence clinched the regular-season title over the weekend.