Oregon (40-18) took a 1-0 lead in the bottom of the first. Mason Neville walked to lead off the inning, took second base on a sacrifice bunt by Chase Meggers and scored on a single by Drew Smith.

The Ducks added a run in the fifth after No. 9 hitter Bryce Boettcher walked with two outs, moved to second on a wild pitch and scored on a single by Neville.

Oregon’s final tally came on a Jacob Walsh home run leading off the bottom of the seventh.

Seitter (8-4) surrendered four ground-ball singles, including two in the ninth to put runners at the corners and bring the tying run to the plate. He struck out Jonah Sebring swinging on a 2-and-2 pitch to end it. Seitter walked one, struck out six and hit three batters. He threw 128 pitches to lead the Ducks to their second straight super regional.

Matt Ager (3-4) took the loss for the Gauchos (44-14). He gave up two runs, two hits and two walks in 4 2/3 innings.

Oregon won regional championships in 2012 and last season. The Ducks made their only College World Series appearance in 1954.

UC Santa Barbara made its only CWS appearance in 2016 when it won its only regional title.