This was one for the defenses.

Grambling’s Brandon Varner stripped the ball away from Southern quarterback Austin Howard, then recovered the late fumble to provide the key play in the Tigers' 30-21 win over the Jaguars in the 44th annual Bayou Classic at the Mercedes-Benz Superdome.

The turnover set up Marc Orozco’s game-clinching 36-yard field goal and spoiled a spirited second-half effort by Southern’s defense.

Martez Carter led the Tigers on the ground with 106 yards and a touchdown on 14 rushes, including the 11-yard touchdown run that gave Grambling the lead for good with 3:22 left. Grambling quarterback Devante Kincaid was 14 of 30 for 171 yards and a score.

Grambling (10-1, 7-0 Southwestern Athletic Conference) moves on to play Alcorn State next week in the SWAC championship game.

“I saw it all week. I had faith,” Varner said of his fumble recovery, which came with 2:44 remaining.

It was Grambling’s 10th straight win this season, third consecutive win in the series, and 25th consecutive win against a SWAC opponent. The Tigers have not lost a conference game since the 2014 Bayou Classic.

A year after the teams combined for more than 1,000 yards of offense in a 52-30 Grambling win, it was defense that made the difference this time.

Southern (7-4, 5-2) trailed 17-7 at halftime but rallied to take its only lead at 21-20 on Howard's 8-yard touchdown pass to Dillon Beard with 5:02 left. The Jaguars defense limited Grambling to 79 yards in the second half, making the comeback possible.

“We had to realize this might be our last 30 minutes of playing football,” Southern defensive lineman Aaron Tiller said. “We played like it was our last 30 minutes of football. Sometimes things don’t go in your favor, but we played a hell of a second half.”

Grambling’s defense took its turn in the spotlight when Southern took over at its own 14 with 3:20 left to play. Trailing 27-21, Southern had time to go the length of the field for a go-ahead score. Instead, Varner sacked and stripped Howard on second-and-3.

“I didn’t see (Varner),” said Howard, who finished his final game at Southern completing 24 of 41 passes for 198 yards with two touchdowns and two interceptions. “I still don’t know what happened. All I know is I was getting ready to throw and I got hit from the back side. The ball came out.”

Grambling’s De’Aumonte Johnson finished off the Jaguars with an interception with 1:23 remaining. Grambling was able to celebrate early as it ran off the final seconds.

Were it not for two long Grambling kick returns, Southern might have pulled out the win. The first came early in the fourth quarter. Malik Route’s 28-yard punt return set up Orozco’s 37-yard field goal to put the Tigers up 20-14.

The one that hurt the most was Route’s 40-yard kickoff return after Southern had taken its 21-20 lead. The return set Grambling up at the SU 40, and the Tigers needed just six plays to take the lead back.

“We got the momentum, gave the ball back to them and they got the momentum,” Southern coach Dawson Odums said. “This game went back and forth.”

Southern also had missteps with its placekicking. Cesar Barajas missed a 25-yard field goal in the first half and had a 37-yard try blocked early in the third quarter.

Dakavion Champion’s fumble recovery gave Southern the ball at the Grambling 40 late in the third quarter. Howard lofted a 20-yard strike to Kendall Catalon in the right corner of the end zone to pull Southern within 17-14.

In the first half, Southern hurt itself with a turnover and unforced mistakes.

On the game’s first play from scrimmage, Ja'Terrious Pouncy picked off an overthrown Howard pass at the SU 36. That set up a seven-play drive that ended when Kincade kept the ball and and rolled into the end zone over Tiller for a 7-0 lead.

After the teams traded punts, Southern put together a 15-play, 72-yard drive but came away with nothing. The Jaguars held the ball for eight minutes, but Barajas shanked a 25-yard field goal try.

Grambling converted 6 of 8 third down chances, and scored on three of its four first-half possessions. In the second quarter, the Tigers finished off an 80-yard drive with Kincade’s 9-yard pass to Carter for a 14-0 lead.

Southern responded by going 67 yards in 12 plays. Howard converted two third downs early in the drive. The first went 11 yards to Jamar Washington, and the second was a 24-yarder to Chase Foster. Devon Benn’s 1-yard run over right tackle had Southern within 14-7 with 3:40 left in the half.

Marc Orozco’s 42-yard field goal on the last play of the half gave the Tigers a 17-7 lead at halftime. One play earlier, Southern had a chance for a drive-stopping interception, but Kincade's pass bounced off Demerio Houston's facemask in the end zone.

Follow Luke Johnson on Twitter, @ByLukeJohnson.