Pat Cunningham began the first game of the National Amateur Baseball Federation College Division World Series yesterday as a reserve. He ended up a hero. Cunningham, who entered the game in the bottom of the seventh inning, went 1 for 1 with a grand slam and six RBI. His bases-loaded walk in the bottom of the ninth inning helped Bethesda defeat the Ohio Warhawks, 18-17, at Joe Cannon Stadium in Dorsey, Md.

Bethesda, which qualified for the tournament by placing second in the Clark C. Griffith Collegiate Baseball League, plays the Bloomington Bobcats at 10 a.m. today in the second round of the double-elimination tournament. Ohio plays at 7 p.m. tonight.

"I was just trying to put the ball in play and make something happen," said Cunningham (Centreville) of his pinch-hit grand slam.

Bethesda trailed 13-8 after six innings, but loaded the bases in the bottom of the seventh as Gregg Davies (Sherwood), Dan Woodley (Paul VI) and Matt Swope (DeMatha) walked. Two batters later, Cunningham hit a 3-2 pitch over the fence in left-center to cut the lead to 13-12.

Ohio scored one run in the eighth off Bethesda reliever P.J. Martinez (Landon), but the Big Train sent 10 men to the plate in the bottom of the inning and scored four runs on three hits. Davies, Jeff Haines and Woodley each walked, Swope (4 for 6) hit an RBI single to left and Jeff Mackey (Landon) hit a two-run single to right. Cunningham followed with a sacrifice fly to center, giving Bethesda a 16-14 lead.

The lead didn't last long. Ohio sent nine men to the plate in the ninth and scored three runs on five hits. Danny Lopaze (Potomac) tripled to right-center, David Chroniger hit an RBI single to left, Tony McQuade doubled to left and Brandon Crowe hit a two-run single to center, giving the Warhawks a 17-16 lead.

Bethesda loaded the bases in the bottom of the ninth as Haines was hit by a pitch and Swope and Mackey each singled to center. Mackey then tied the game with a bases-loaded walk, setting the stage for Cunningham's game-winning walk.

"The big thing is we won," said Bethesda Manager Derek Hacopian, whose team was outhit, 25-19. "It wasn't pretty, but we won."

Ohio 004 270 013 -- 17 25 3

Bethesda 123 011 442 -- 18 19 2

2B: Davies, Swope, Easter, Butler, Bodenmiller, Chroniger, McQuade; 3B: Oliva, Woodley, Lopaze; HR: Cunningham, Pabon, Lopaze. Ohio: Prochaska (1), Huber (7), Olson (7), Fordham (8), Braden (8), Crowe (9) and Chroniger; Bethesda: Acors (1), Martinez (5), Abraham (9) and Oliva.