[2] He scored 38 points in an upset of Joseph Wheeler High School in the Les Schwab Invitational during his senior season.

Following the season, Mathis contemplated quitting basketball and eventually asked coach Craig Neal for a release from his scholarship in order to transfer.

While talking with potential schools, Neal was fired and Mathis ended up remaining at New Mexico under new coach Paul Weir.

[5] He averaged 14.4 points, 2.2 rebounds, and 2.1 assists per game as a senior, setting a school record with 106 made three-pointers on 41.6 percent shooting.

[7] On June 5, Mathis committed to Oregon as a graduate transfer, choosing the Ducks over Boston College, Kansas, Houston, Oklahoma, and Texas A&M, among others.