BOONE, N.C. — A rivalry win triggered the return to postseason eligibility.

Senior quarterback Taylor Lamb threw two touchdown passes and a stingy defense kept Georgia Southern out of the end zone as Appalachian State recorded a 27-6 victory in front of an ESPNU audience on Thursday night at Kidd Brewer Stadium.

With the victory, the Mountaineers (6-4, 5-1 Sun Belt) are 3-for-3 in becoming bowl eligible as a full-fledged FBS member.

Tee Sims increased his season total to 9.5 sacks by posting one of three by App State's defense, which limited the Eagles (0-9, 0-5) to 191 yards of offense and prevented them from scoring an offensive touchdown for the second straight year. It was the first time since Appalachian's 19-0 playoff victory in 1987 that Georgia Southern didn't score a touchdown of any kind against its former Southern Conference rival.

Special teams also played a significant role for the Mountaineers, as Chandler Staton's two field goals included a 53-yard kick to end the first half and they moved ahead 20-6 early in the fourth quarter after 241-pound defensive end Caleb Fuller rushed for 23 yards on a fake punt.

Three plays after Fuller advanced to the Georgia Southern 27 on his fourth-and-3 carry from midfield, Lamb threw a 20-yard touchdown pass to Ike Lewis to give the senior receiver his seventh touchdown in the last five games and push the quarterback's season total to 21 TDs with only four interceptions. True freshman Daetrich Harrington produced his first career touchdown on a 3-yard run to cap the scoring with 9:40 left.

After the Eagles opened the scoring with a 29-yard field goal, Lamb gave App State the lead for good on a 27-yard touchdown pass to tight end Collin Reed midway through the second quarter.

Trailing 7-3, Georgia Southern used a fourth-down stop to begin a drive at App State's 36 with 2:20 left in the half, but Sims' first-down tackle in the backfield facilitated a three-and-out possession that ended with a punt from the 42. Seemingly content to enter halftime with a four-point lead, App State let the clock run before Lamb gained 44 yards to the Georgia Southern 35 on a third-and-9 draw. The Mountaineers called a timeout with three seconds left, and Staton drilled the 53-yard field goal as the half ended.

It was the sixth-longest field goal in school history and the longest successful attempt since Mark Wright set a school record with a 57-yard field goal against Troy in 2000.

Staton added a 28-yard field goal early in the third quarter, making him 5-for-5 in the last three games, and the Eagles converted a 44-yard field goal before App State successfully executed the fake punt from midfield with a 13-6 lead.

Lamb completed seven of his 13 passes for 161 yards, and redshirt freshman Marcus Williams Jr. rushed for a career-high 130 yards in his third straight start for the Mountaineers, who played without injured back Jalin Moore.

Austin Exford and Rashaad Townes joined Sims in recording a sack, and A.J. Howard had seven solo tackles to lead App State, which gave up 159 yards of offense in its 34-10 victory against Georgia Southern last season. The Eagles scored their only touchdown that night on the 90-yard return of a field goal miscue, and they had 141 yards of offense when they started their last drive with 1:35 remaining Thursday.