Red Raiders guard Matt Mooney attempted to block a 3-point attempt near the corner, and his momentum carried him directly in front of Routt on the West Virginia bench.
Routt moved his legs together and in the process trapped Mooney's leg between them, which caused the Texas Tech senior to trip and fall to the court.
After consulting video of the play, officials issued Routt with a Flagrant 2 foul, which carries an automatic ejection.
"I didn't see it personally. Two of our coaches did. The refs did a good job of finding the play,'' Texas Tech coach Chris Beard said.
Moretti made both free throws after the flagrant technical, and Mooney hit a 3-pointer to finish the possession for a 49-22 lead.
The Mountaineers would go on to lose in a rout, 81-50.
The Associated Press contributed to this report.