The Bulldogs defeated No. 3 Oregon State, 4-1, in Friday's opener, while UCLA beat top-seeded North Carolina, 4-1, in the nightcap at TD Ameritrade Park to set up what promises to be an intriguing and well-played College World Series final.
Mississippi State (51-18) and UCLA (47-17) open the best-of-three series at 8 p.m. ET on Monday.
"They're on a roll just like we are," UCLA coach John Savage said. "I mean, to beat Oregon State -- we know how good Oregon State is. They're good. And to do what they did against them twice, it goes to show you that they're a little better than them."
While the homer by Renfroe -- the 13th overall pick by the Padres in the 2013 First-Year Player Draft -- sent the Bulldogs to the finals, UCLA perfectly executed its brand of baseball to join them there.
Batting just .182 and with eight runs in three games in Omaha, the Bruins on Friday once again relied on patience, timely hits and their opponents' mistakes to advance.
First baseman Pat Gallagher and designated hitter Kevin Williams (29th round, Marlins) knocked one-out singles in the second before North Carolina left-hander Kent Manuel (third round, Astros) induced a fly out. But second baseman Cody Regis hit a chopper through the right side to score Gallagher.
UCLA added another run in the sixth in similar fashion -- error, bunt and consecutive singles -- before shortstop Pat Valaika (ninth round, Rockies) followed two walks with a two-run single in the seventh.
"It was our style of baseball. What can you say?" Savage said. "It was pitching, solid defense, opportunistic offense. ... It was a great evening for us."
UCLA left-hander Grant Watson allowed four hits in six scoreless innings and the Bruins bullpen followed suit until David Berg allowed one in the ninth, but ended the game by leaving the bases loaded.
"You saw how they got their four runs, and you've got to be a little lucky and you've got to be opportunistic and take advantage," North Carolina coach Mike Fox said. "And we just weren't able to do that tonight."
Renfroe's three-run homer in the opener backed right-hander Kendall Graveman (eighth round, Blue Jays), who tossed 5 2/3 innings of one-run ball after the Beavers scored four runs (two earned) against him last Saturday.
"Graveman did a great job today and was able to throw the ball on either side of the plate, gave us some different looks from the mound offensively that we didn't see the first game," Oregon State's Michael Conforto said.
Graveman retired the first seven batters he faced, surrendered four hits and only allowed a sixth-inning RBI single to Andy Peterson. Lefty Ross Mitchell tossed 2 2/3 shutout innings while Jonathan Holder got the game's final two outs to secure the victory.
Renfroe extended a 1-0 lead in the fifth when he sent Oregon State right-hander Andrew Moore's offering into the left-field bullpen for a three-run homer.
"[Oregon State coach Pat Casey] called a 3-1 curveball. I tried to bury it because we had a base open and I made a mistake, left it open a little bit," said Moore, who allowed four runs in 4 2/3 innings. "He's a great player. Made me pay for it."
This is the Mississippi State's first-ever appearance in the finals, while UCLA advances to its second-ever -- the first was in 2010. Both programs are in search of their first national championship.
"It looks to be similar teams," Savage said, noting Mississippi State's impressive pitching and offense. "I guess you could say that on paper they would be more offensive. But we take care of the baseball defensively, and we pitch and we know ourselves. So right now, we're certainly going to respect Mississippi State in the job they've done. But at this stage it's really what you're doing as a team and how you're preparing."
Mississippi State 4, No. 3 Oregon State 1
UCLA 4, No. 1 North Carolina 1
UCLA vs. Mississippi State, 8 p.m. Monday
Mississippi State vs. UCLA, 8 p.m. Tuesday
UCLA vs. Mississippi State, 8 p.m. Wednesday (if necessary).