The Bulldogs (51-18) beat the Beavers for the second time in the CWS and will play for the first time in the best-of-three championship round that starts Monday against the winner of the North Carolina-UCLA matchup.
Oregon State (52-13) went 2-2 in its first CWS appearance since winning back-to-back national titles in 2006-07.
Renfroe’s homer off freshman left-hander Andrew Moore (14-2) was only the third in 11 CWS games and put the Bulldogs up 4-0 in the fifth.
Kendall Graveman (7-5) worked the first 5 2-3 innings, allowing one run on four hits. Ross Mitchell and Jonathan Holder finished, with Holder getting the last two outs for his 21st save of the season and school-record 30th of his career.
It’s the sixth straight year a team from the Southeastern Conference has reached the finals.
The Bulldogs built on a 1-0 lead after Moore retired their first two batters in the fifth. Adam Frazier and Alex Detz singled before Renfroe, the No. 13 overall pick by San Diego in the recent draft, drove Moore’s 3-1 breaking ball for his first home run since May 4 and 16th of the season.
Moore gave up four runs on nine hits in 4 2-3 innings, his shortest outing of the season. Jace Fry pitched 3 1-3 innings of two-hit shutout relief, but the Beavers’ offense couldn’t crack Mitchell and Holder.
Mississippi State had beaten the Beavers 5-4 in the CWS opener, with Danny Hayes’ deep fly to right dying on the warning track in the bottom of the ninth inning.
There was no such drama this time.
The Bulldogs’ Brett Pirtle extended his streak of reaching base to 42 games, and Renfroe extended his hitting streak to 10 games.
Graveman also started the first game against the Beavers, but he allowed four runs in 4 2-3 innings that day and was let off the hook when Wes Rea doubled in the winning runs in the eighth.
Graveman, the eighth-round draft pick of the Toronto Blue Jays, is now 3-0 in four NCAA tournament appearances.
Oregon State left fielder Michael Conforto turned in perhaps the best defensive play of the CWS when he robbed Wes Rea of extra bases in the second inning. Conforto retreated to the warning track on Rea’s fly, jumped to make the catch and held on as he slammed against the wall.
Beavers shortstop Tyler Smith was so impressed that he went out to left to give Conforto a hug.