The Rebels and Thoroughbreds were tied 10-10 in the 10th when Yarbrough sent a 1-2 pitch over the right field wall.
In the eighth inning of Sunday's 7-6 win against LSU, the freshman second baseman hit his first round-tripper as a collegian, a solo shot that made it 6-6.
Yarbrough appeared to wear an even bigger smile following the win Tuesday than he did Sunday.
"I don't know what it is," said Yarbrough of his newly-found strength.
"He hung a curve ball with two strikes, and I got my foot down and saw it all the way," he said. "I stayed back just long enough."
Ole Miss scored 10 runs through five, and starter Matt Crouse held Murray State to just a run through six. That's when things got really interesting, however.
Reliever Jordan Cooper gave up six runs in the seventh, including a grand slam. MSU actually scored seven runs in the frame.
The Rebels scored in every inning through five but no more after that - until the 10th. In the first, Matt Smith drove in Tim Ferguson with a base hit after the Rebs' center fielder had walked.
In the top of the second, Murray State picked up its lone run through six innings. In the bottom of the second, the Rebels added two more runs. Ferguson singled to score Taylor Hightower who had doubled. Miles Hamblin then doubled to score Ferguson.
In the third, Kevin Mort singled to score Matt Snyder who had walked. A David Phillips base hit got Zach Miller home who had also reached via the free pass.
In the fourth, Ole Miss added three runs Matt Snyder singled to score Hamblin who had gotten on base with a single. A Mort base hit scored Matt Smith who had reached on a single. A Taylor Hashman fly ball scored Snyder from third.
The Rebels then stretched the lead to 10-1 in the fifth on solo home runs by Ferguson and Smith. Smith was 4-for-6 in the game, and Hightower went 4-for-5.
After a scoreless inning for both ballclubs, out came Crouse and in came Cooper. And the seven-run inning ensued. Six runs on three hits with two walks and no strikeouts later, Matt Tracy relieved Cooper.
It was still 10-8 after eight innings. Following a leadoff single by Bryan Propst in the ninth, Bianco pulled Tracy (who stayed in to DH).
Brett Huber came in and for a bit, things continued to be a struggle. Drew Pixley and Daniel Hill both got base hits to load the bases. They stayed loaded when Cory Hodskins sent a ball to Matt Smith in right field. But the strong-armed Smith threw a strike to catcher Hightower that forced the runners to stay put.
After Jonathan Craycraft struck out, Colton Moore hit the baseball to Miller at third. But Hamblin at first wasn't able to handle the throw, and two runs scored tying the contest. Zach Noonan then struck out.
After a scoreless bottom of the ninth and top of the 10th, up came Yarbrough, who is having quite a first season of college baseball.
"A crazy baseball game," said Ole Miss head coach Mike Bianco. "What gets lost in it is our 20 hits and 11 runs. And a great outing by Crouse.
"Credit Murray State," he continued. "They've been struggling, and to be down 10-1 on the road, it's amazing. You don't see things like that very much. I love the way we responded. Nobody really panicked. And then Alex gets the big hit."
Huber (2-0) got the win and Will Handlin (0-1), the last of five MSU pitchers in the game, got the loss.
"It's tough," Yarbrough said of his team losing such a big lead. "That came out of nowhere. I'm just glad we could come back and finish it. Coach told us (before the bottom of the 10th inning) it's a crazy game, and stuff like this happens every day somewhere in the country."
And then he headed to the plate and won it.
Ole Miss (29-13) hosts Tennessee-Martin Wednesday at 6:30 p.m. The Rebels will start junior right-hander Eric Callender (2-1, 5.23 ERA).
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