Defending Interhigh League baseball tournament champion Wilson and surprising Eastern used big innings to build big leads en route to semifinal victories yesterday at RFK's auxiliary field.

Eastern (10-4), seeking its first tournament title since 1975, plays Wilson (11-4) for the crown today at 2.

Antoine Williams stroked a three-run homer, Chris Lundblad had a triple and double and five RBI, and Chris Myers had four singles as Wilson rolled to an 18-5 triumph over H.D. Woodson.

Hit hard by Ballou in his final regular season game five days ago, Kevin Waymer turned in a gutty performance on the mound and had a two-run triple as Eastern avenged the loss, 12-9.

The Ramblers, who registered a a 22-4 thrashing of Dunbar in the quarterfinals, had nine hits and were aided by eight walks and four errors. The Knights committed three of their errors and walked four batters in a five-run second inning that broke a 1-1 tie, keyed by Rodney Motley's two-run single.

Ballou, trying to save ace John Beals for the title game, had no choice but to use the right-hander, but most of the damage had been done by the time he came in. Beals gave up eight hits, including the triple by Kevin Waymer and a two-run homer by his brother, George.

Kevin Waymer, beaten 13-5 by Ballou in the game that gave the Knights (9-3) the division title and a first-round bye in the tournament, wasn't so sharp. He struck out seven but allowed eight walks and nine hits, including home runs by Kwame Spinks and Bo Lawton. But each time he appeared to be in serious trouble, he managed to get the third out.

"I think Ballou may have overlooked us a bit because they didn't go with their best pitcher," Eastern Coach Tillman Frizzell said. "I had to throw my best and let tomorrow take care of itself. The kids were a bit nervous at times but they usually don't rattle. They settled down and Kevin pitched much better than he did the other day. I have no idea who will pitch the last game but we're in the championship game."

Woodson's dream of making the title game lasted only minutes after Tony Copeland's two-run homer gave the Warriors (8-5) a 2-0 lead in the second. In the bottom of the inning, Williams's homer gave Wilson the lead for good, 3-2.

Williams, who walked three times and scored four runs, then scored on a wild pitch in a three-run fourth and again in the fifth, when Wilson scored seven runs to take a 13-2 cushion.

"We didn't start hitting until the end. But we got that big home run to get us going," Wilson Coach Marc Harris said. "I was surprised we got a good job from our pitcher, Zeke Shaub. We were hoping for at least three innings and he went six."

Harris, who plans to start Williams today, gave his ace an inning in relief of Shaub. "I just wanted him to loosen up some, throw a little," Harris said.