MOBILE, Ala. (AP) No. 21 Appalachian State has proven to be explosive on offensive and opportunistic on special teams this season. On Saturday, at a rain-soaked Ladd-Peebles Stadium, the Mountaineers relied on a dominating defense to roll to a 30-3 victory over South Alabama.

Appalachian State (7-0, 4-0 Sun Belt) took a 23-0 lead with 3:45 left in the third quarter. At that point, South Alabama had not run a play beyond midfield and had gained only 43 yards and one first down on 32 offensive snaps.

''I thought our defense played unbelievable today and held them in check all day,'' Appalachian State coach Eli Drinkwitz said. ''It really allowed us offensively to kind of find ourselves. We struggled converting third downs and really didn't play solid enough offensively, but we played well enough to win and we'll be on to the next one.''

Offensively, Zac Thomas had a successful return to his home state. The reigning Sun Belt Conference Player of the Year passed for 132 yards, including a 19-yard TD to Thomas Hennigan, without a turnover. The Hewitt-Trussville High School graduate has led the Mountaineers to 13 consecutive victories, which trailed only Clemson and Ohio State entering the game.

The Jaguars (1-7, 0-4) were held to a season-low 139 total yards. The previous low was 190 in a loss to UAB. South Alabama avoided the first home shutout in school history with a 37-yard field goal by Frankie Onate with 5:43 remaining.

''I thought defensively we played well enough to win the game,'' second-year USA coach Steve Campbell said. ''Offensively, we've got to figure out what we need to do to score some points. We've definitely got to move the ball better than we did today.''

SHORT FIELD SUCCESS

The Mountaineers didn't produce many explosive offensive plays, but they didn't need to. Because the defense was so suffocating, their five scoring drives covered only 44, 12, 34, 62, 49 and 69 yards.

THE TAKEAWAY

Appalachian State: The No. 21 ranking has the Mountaineers just behind No. 16 SMU and No. 18 Cincinnati and just ahead of No. 22 Boise State among Group of Five teams. Appalachian State is the first Sun Belt Conference team to be ranked in consecutive weeks.

South Alabama: The Jaguars produced no offense until turning to backup quarterback Desmond Trotter midway through the third quarter. The redshirt freshman from Birmingham provided a spark by leading USA to a 65-yard drive that ended in a 32-yard field goal attempt that was blocked. He then led the fourth-quarter field goal drive.

POLL IMPLICATIONS

Appalachian State should at least maintain its national ranking after Saturday's defensive showing.

UP NEXT

Appalachian State visits Georgia Southern, which knocked the Mountaineers from the rankings last season, on Thursday night. The Panthers beat the Mountaineers a year ago this week. The Mountaineers haven't lost since.

South Alabama visits Texas State on Nov. 9 after an open date.

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