OSU improved to 18-9 on the year while UALR dropped to 18-12.
The Pokes took an 8-0 lead in the second with seven of the runs coming off a three-run homer by leftfielder Scott Kirby and the grand-slam homer by Fields. The final run in the inning came off a RBI single by designated hitter Mario Matulich.
Arkansas-Little Rock cut into the lead in the fifth with a three-run homer by right fielder Aaron Haefele. Those were the only runs Cowboy starter Justin Ottman (1-0) would give up in his five innings of work. He allowed just four hits with five strikeouts and just one walk to pick up his first win in an OSU uniform.
Kirby would add his second homer of the evening, a solo shot, in the bottom half of the inning to extend the lead to 9-3. The Trojans scored two runs in the sixth on a RBI single by first baseman Brodie Ward and on an error by centerfielder Jose Virgil to cut the advantage to 9-5.
UALR added a run in the eighth on a bases loaded walk by shortstop Matt Spatafora off of Cowboy closer Daniel Rew. The Pokes added three insurance runs in the bottom of the inning to make it 12-6.
Arkansas-Little Rock made it interesting in the ninth by adding two more runs on a solo homer by catcher Rick Guarno and a RBI single by first baseman Brodie Ward to cut the lead to 12-8. The Trojans had runners on first and second with two outs before Rew got Haefele to fly out to center to end the game.
Oklahoma State will be back in Big 12 play this weekend against Kansas State at Reynolds Stadium. The series opens on Friday at 6 p.m. with Cowboy right hander Scott Baker slated to take the mound.