Alexander made 13 of 15 free throws. He added eight rebounds.
Mitch Ballock had 11 points for Creighton (8-2), which earned its fourth consecutive win.
The Bluejays forced a season-high 20 turnovers.
Creighton dominated the first half and led 45-24 at the break. The Vaqueros' 24 points in the first half were a season low for the team.
Creighton faces Oklahoma at home on Tuesday. Texas Rio Grande Valley takes on Nebraska Omaha on the road on Sunday.
For more AP college basketball coverage: https://apnews.com/Collegebasketball and http://twitter.com/AP-Top25
This was generated by Automated Insights, http://www.automatedinsights.com/ap, using data from STATS LLC, https://www.stats.com
Tar Heels' Brandon Huffman says he's transferring
Brandon Huffman, a 6-foot-10, 255-pound junior who played in 14 games for North Carolina this past season, plans to transfer, calling it a "rough decision to make" in a social-media post.
Georgia Tech's eligibility for 2021 postseason confirmed by NCAA
Georgia Tech athletic director Todd Stansbury says the school's men's basketball team will be eligible for the 2021 postseason.
Poll: Sports fans won't attend games without coronavirus vaccine
A majority of fans in a recent poll said they would not attend games before a vaccine is developed for coronavirus.