NEWARK, N.Y. -- Cortland State broke open a tight game with a four-run seventh inning and the nationally fifth-ranked Red Dragons defeated Castleton State 6-1 during the opening day of the NCAA Division III Baseball regionals at Colburn Park.

Cortland (32-8), the top seed in the eight-team regional, will face fifth-seeded Farmingdale State at 4:30 p.m. ET on Thursday in a winner's bracket game. Castleton (29-11), the eighth seed, will play fourth-seeded Rutgers-Camden in an elimination game at 10 a.m. Thursday.

Brandon McClain started for Cortland but left the game in the third inning after dealing with a minor injury. He did not allow any hits but walked four batters, including the last three he faced, in two and two thirds innings. He struck out five.

Ryan McAlary relieved McClain and was awarded the win after giving up one hit and five walks in three and a third innings. He fanned three batters and is now 2-0 on the season. Steven Kimmelman pitched three scoreless innings for his second save. He struck out three, walked one and allowed three hits.

Up 2-1 in the seventh, Cortland recorded five of its 11 hits as it extended its lead to 6-1. Tim Panetta opened with a bad-hop single, moved to second on an Anthony Simon sac bunt and scored on Mark DeMilio's RBI double to right. With two outs, Conrad Ziemendorf hit an RBI single, Anthony Iacomini hit an RBI double and P.J. Rinaldi singled in a run.

Cortland scored twice in the bottom of the first. Donny Castaldo beat out a grounder to short and Ziemendorf was hit by a pitch. Iacomini bunted the runners to second and third and Rinaldi hit a two-run single through the right side.

Castleton scored in the third on consecutive walks by Tyler Lord, Allen White, Joe Borowski and Daniel Errico. The Spartans stranded runners on second and third in the fourth, and in the fifth they had runners on first and third with one out before two McAlary strikeouts ended the threat.

Castleton also threatened in the seventh with a Daniel Errico two-out walk, a steal and a Matthew McNamee infield single, but Kimmelman fanned the next hitter to stop the rally.

Rinaldi finished 2-for-4 with three RBI and Max Rosing was 2-for-4 for the Red Dragons. For Castleton, Soren Pelz-Walsh was 2-for-3 and White drew threw of the Spartans' 10 walks. Castleton starter Samuel Spencer allowed 11 hits, two walks and six runs during seven innings.

Cortland has opened regional play with a win against Castleton in three of the last five seasons. The Red Dragons beat the Spartans in Auburn 10-2 in 2010 and in Farmingdale 7-6 in 2012.