Denton Ryan was an afterthought going into the playoffs after finishing third in District 4-4A behind Little Elm and The Colony.
Now the Raiders are a win away from their first state tournament berth since winning state in 2000.
Trey Mohair hit a layup at the buzzer to give Ryan a second consecutive stunning upset, this time a 58-56 win over Fort Worth Trimble Tech on Friday.
Ryan advances to play Fort Worth Arlington Heights at 2 p.m. Saturday at The Coliseum in Snyder.
"It had to have spun on the rim for 30 or 40 seconds it seems like before it dropped," said Ryan head coach Bryce Overstreet, who is enjoying a career year with Ryan.
Ryan held a seven-point lead with 39 seconds remaining before Trimble Tech connected on a 3-pointer and a four-point play to tie the score in stunning fashion.
On the final play of the game, Mohair, who continued his scorching pace in the playoffs with 28 points, went coast-to-coast and split two defenders to sink the winning bucket.