Peter O’Brien could have completed the cycle Sunday afternoon at Alex Rodriguez Park. But a single, double and two home runs — minus the triple — had to suffice.

Not a bad day’s work for the 6-5, 225-pound All-American senior who transferred to the University of Miami this season after three years at Bethune-Cookman.

O’Brien went 4 for 5, including a home run to right field in the third inning and another to left field in the sixth, and drove in three runs to lead the Hurricanes to a 9-7 victory and opening-series sweep against Rutgers.

“I was seeing the ball good,” said O’Brien, who also threw out a runner attempting to steal. “I felt confident. I felt like the hitters in front of me worked the counts and let me see the pitcher before I got in there. It’s easy when you feel good.”

By the end of the four-hour game, only a smattering of the 2,755 fans remained, but they cheered boisterously for their team’s 3-0 start.

On Saturday night, the Hurricanes went 12 innings in 3 hours 40 minutes before they defeated the Scarlet Knights (0-3) with a walk-off home run by Rony Rodriguez.

“You’ve got to be tough mentally,” O’Brien said, “but the biggest thing is we worked our butts off in the fall lifting hard and came back in the spring doing all that running. That’s where conditioning pays off.”

Unlike in the first two games of the series, Miami’s pitching stumbled from the start Sunday. Sophomore Bryan Radziewski, last year’s No. 1 starter, struggled by allowing four earned runs on seven hits and four walks in 3 2/3 innings. He threw 84 pitches in that short stint.

Alex Fernandez, the son of former UM and Marlins pitcher Alex Fernandez, pitched only a third of an inning to earn his first college victory. Fernandez walked two and struck out one.

E.J. Encinosa pitched the final inning to earn his first save.

The Hurricanes’ seven pitchers combined for five strikeouts and eight walks, while hitting three batters. Saturday, the Canes staff struck out 16 and walked two.

“We played good defense again but struggled pitching-wise for the first time,” UM coach Jim Morris said. “[Sunday] was a day for the hitters. They did a great job of answering back every time Rutgers scored.”

The play of the game came in the sixth inning, when UM right fielder Chantz Mack made a spectacular diving catch to rob Russ Costello of a potential extra-base hit with the bases loaded.

UM freshman shortstop Jarred Mederos, who graduated from Mater Academy and grew up in Hialeah, had his first hit, first RBI and first two stolen bases Sunday. He also had an error.

“It was amazing to finally start in college,” Mederos said. “I finally got on top of the ball and started driving the ball a lot better.”

Morris said opening-day center fielder Julian Santos pulled a hamstring Friday and that he hoped Santos would be back by next weekend. The Canes next play at Florida Gulf Coast in Fort Myers at 7 p.m. Wednesday.