Northeast will face Southeastern in the championship round Monday.
Kirkwood topped Northeast, 5-3, in the opening round of the tournament Thursday, but the Hawks jumped to a 5-0 lead in the second inning Sunday and never lost the lead.
The Eagles scored three runs in the top of the fifth inning to pull within 5-3, but Northeast tallied twice in the seventh for a 7-3 advantage to give itself some breathing room.
Kirkwood Coach Todd Rima and the Eagles finished with a 33-20 record. They went 2-2 in the regional.
Kirkwood 000 030 010 - 4 8 3
Northeast 320 000 20x - 7 9 3
Krob, Nigut (3), Fuller (6), Bennett (7), Frese (7) and Thompson. Taylor, Rodriguez (8) and Walker. W - Taylor (8-2). L - Krob (2-6). 2B - Youngquist. RBI - Youngquist, Thompson 3.