BOONE, N.C. (AP) _ Leonard Harris ran for two touchdowns in the fourth quarter Saturday, leading Stephen F. Austin to a 27-17 victory over previously unbeaten Appalachian State in the NCAA Division I-AA playoffs.

The Lumberjacks (11-1) will travel to Montana for a semifinal meeting with the Grizzlies, who defeated Georgia Southern 45-0 in the quarterfinals.

It's the first time Stephen F. Austin has been to the semifinals since 1989, when it eventually lost to Georgia Southern in the championship game.

Stephen F. Austin's offensive line opened huge holes, helping Harris gain 180 yards on 25 carries. The Lumberjacks finished with 267 yards rushing and 436 overall.

In the meantime, the ground-oriented Appalachian State offense couldn't budge the Lumberjacks' defense, picking up just 72 yards on 34 carries.

Each team committed a turnover at the start of the third quarter, but it was the Mountaineers (12-1) who capitalized to take the lead.

Quarterback Scott Satterfield fumbled inside the Lumberjack 25 and defensive end Kevin Reynolds recovered. Six plays later, quarterback James Ritchey fumbled and Jason Hatcher fell on it for the Mountaineers at their 47.

It took six plays for Appalachian State to get the lead, capping the 53-yard drive with Satterfield's 6-yard pass to Aldwin Lance with 6:42 left in the third period.

Appalachian State failed to take advantage of another fumble midway through the fourth quarter, and the Lumberjacks struck in a hurry.

Aided by a 49-yard pass play from Ritchey to Chris Jefferson, Harris dashed up the middle and scored from 2 yards out with 4:12 to play, giving Stephen F. Austin a 20-17 lead.

Satterfield was sacked at his 30 on fourth down, setting up Harris' clinching 6-yard run with 1:38 to go.

Appalachian State turned an interception on the Lumberjacks' first possession into a 7-0 lead when Satterfield hit tight end Frank Leatherwood with a 2-yard scoring pass at 8:17. The Lumberjacks wasted no time retaliating, getting Brian Minton's 31-yard field goal with 3:51 left in the period.

The Lumberjacks went up 10-7 on Dameian Vallery's 17-yard scoring run with 1:04 left in the period and added a 20-yard field goal by Minton in the second quarter.

Appalachian State got a 31-yard field goal by Jay Sutton with 33 seconds left in the half.