Josh Swogger passed for 230 yards and two touchdowns to Craig Chambers and Montana's defense only allowed Southern Illinois past midfield twice in a 20-3 quarterfinal win Saturday.
No. 2 Montana (12-1) extended its winning streak to 12 games and advances to the semifinals for the eighth time in school history. The Grizzlies play UMass, a 24-17 winner, next week.
Craig Coffin kicked a 27-yard field goal with 10:09 remaining for No. 10 Southern Illinois (9-4).
Swogger hit Chambers on a 4-yard TD pass with 14:15 left in the half and on an 8-yard scoring pass with 6:05 remaining.
Dan Carpenter kicked field goals of 43 yards in the first quarter and 38 yards in the second and ran for a first down on a fake punt in the third quarter.
The Grizzlies held Arkee Whitlock, the fourth-leading rusher in I-AA, to 80 yards, 66 below his season average.
The Salukis had just 129 yards in total offense, compared to their season average of 393.
UMASS 24, NEW HAMPSHIRE 17: Liam Coen passed for 231 yards and two touchdowns and host Massachusetts withstood a determined New Hampshire bid in the final seconds in Amherst.
UMass (12-1) has won 10 straight and plays at Montana.
Massachusetts, which trailed 17-14 at halftime, blanked the Wildcats in the second half after having beat New Hampshire (9-4) 28-20 earlier in the season.
UMass went ahead for good late in the third quarter on a 31-yard touchdown pass from Coen to Brandon London that made it 21-17. The Minutemen tacked on a final three points on Chris Koepplin's 33-yard field goal early in the fourth quarter.
New Hampshire's late drive was halted with 33 seconds to play, when Rick Santos' pass was deflected to the ground on a fourth-and-1 play from the 6.
APPALACHIAN STATE 38, MONTANA STATE 17: Kevin Richardson rushed for 131 yards and four touchdowns in Boone, N.C., and defending national champion Appalachian State won easily.
Quarterback Armanti Edwards rushed for 105 yards and a score - the second straight week he and Richardson both went over 100 yards on the ground - and Omarr Byrom had 31/2 sacks and a forced fumble as the top-seeded Mountaineers won their 12th straight game.
Appalachian State has won 26 straight home games and advances to play Youngstown State.
YOUNGSTOWN ST. 28, ILLINOIS ST. 21: Tom Zetts threw for two touchdowns and ran for another as the host Penguins (11-2) withstood a fourth-quarter rally in Ohio against the Redbirds (9-4).