Darien Chase’s 3-pointer with seven seconds left gave Mountain View home victory.
The Thunder trailed 52-50 after Spencer Long hit two free throws with 20 seconds left.
From the top of the key, Chase dribbled to his right, then hit a step-back 3-pointer in front of his defender.
Long had a chance to win it for River, but his off-balance five-footer was off the mark at the buzzer.
Mountain View (2-1), which was 8-13 last year, has now held close to a top 4A team in Union and beaten last year’s 3A Greater St. Helens League champ in Columbia River.
“I feel like we’re closing the gap,” Thunder coach Aaron Shepherd said. “With each win like this, our confidence grows. They believe they can play with anybody.”
Trevor Green had 12 points and 12 recounds for Mountain View. Alex Bailey also scored 12 points.
Jacob Hjort scored 24 points to lead Columbia River (2-1). Long added 15 points.
The Chieftains trailed 31-20 at halftime, but outscored Mountain View 21-7 in the third quarter.
MOUNTAIN VIEW 53, COLUMBIA RIVER 52
COLUMBIA RIVER (2-1) — Kaden Dezort 2, Conner Wells 0, Mason Waite 0, Jacob Hjort 24, Evan Dirksen 0, Nathan Hockhalter 7, Nasseen Gutierrez 1, Spencer Long 15, Jack Armstrong 3. Totals 16 (6) 14-18 52.
MOUNTAIN VIEW (2-1) — Rodolfo Montiel 4, Jack Mertens 0, Darien Chase 11, Alex Hegel 8, Makai Anderson 4, Trevor Green 12, Alex Bailey 12, Cameron Henderson 2, Troy Pacheco 0. Totals 21 (4) 7-13 53.
C.River 6 14 21 11–52
Mt. View 17 14 7 15–53
JV — Columiba River won.
C — Mountain View won.