When it comes to defending the run, Alabama is on a different level. The Crimson Tide are again No. 1 nationally in rushing defense.

First-year Georgia coach Kirby Smart was the ‘Bama defensive coordinator for nine seasons. If there was one part of the Tide program he wanted to take with him to the Bulldogs, it was the ability to eradicate the enemy running game.

In Saturday’s matchup against then-No. 9 Auburn, UGA held the SEC’s premier rushing offense to 127 yards on 32 carries — the Tigers arrived in Athens averaging 299.8 yards per game on the ground — in a 13-7 upset victory. Most impressive, the Dawgs didn’t allow a single first down in the second half to help erase a 7-0 halftime deficit.

While Smart and Co. were eliminated from the East race earlier in the day, they knocked Auburn out of contention in the West.

“We came out the second half, and we just felt like they’re not going to run the ball on us,” said linebacker Roquan Smith, according to 247Sports. “So it was like, if they want to run the ball, we’re just going to stop them.”

Tigers running back Kerryon Johnson finished with 99 yards on a touchdown on 22 carries, although most of his success came early in the contest. The space he found outside the tackle box was gone after intermission.

“That was the adjustment we needed,” Smith said. “They were hitting everything on the perimeter in the first half, so the halftime adjustment was stopping the run there and we stopped it, but I guess they continued to try to do it.”

Auburn fans will point to the fact that bruising ball carrier Kamryn Pettway — the leading rusher in the league with 1,106 yards — was unavailable due to injury. At 6-foot and 240 pounds, he’s a between-the-tackles pounder and a nightmare to bring down if he breaks through the line and gets to the second level.

Oct 8, 2016; Starkville, MS, USA; Auburn Tigers running back Kamryn Pettway (36) runs the ball during the second quarter of the game against the Mississippi State Bulldogs at Davis Wade Stadium. Mandatory Credit: Matt Bush-USA TODAY Sports

Credit: Matt Bush-USA TODAY Sports

In the wake of transfers, dismissals and injuries at the position, Pettway (above) got his opportunity and, quite literally, ran with it.

Pettway had racked up 169, 192, 236 and 173 yards in his previous four games, all against SEC competition. But late in a 23-16 win over Vanderbilt two Saturdays ago, he came up lame with a pulled quad.

Nevertheless, Pettway’s absence shouldn’t take away from Georgia’s spirited effort. Smith — the Bulldogs’ leading tackler — paced the unit with 7 tackles. Defensive tackle Trenton Thompson was a force up front and recorded his team-best sixth tackle for loss. Davin Bellamy, Reggie Carter and Jonathan Ledbetter all had a TFL, too.

“They are a run-first team, and not having their big back was tough,” Smart told 247Sports. “He’s a great player. It’s tough that he wasn’t healthy, but they ran well with the others. Our kids struck and played hard tonight.”

Because UGA forced so many three-and-outs, Auburn wasn’t able to get into a rhythm and run downhill with its up-tempo style.

“That’s huge for a defense when you play Auburn because you’ve got juice,” Smart said. “They’re at their best when they get rolling. If they don’t get rolling, that’s when they struggle more.”

With the running game not nearly as productive as it had been in recent weeks, Tigers quarterback Sean White wasn’t able to make up the difference. The Dawgs’ only TD came on an interception return by Maurice Smith in the third quarter.

Despite coming into Sanford Stadium as the top-rated passer in the conference, White completed only 6-of-20 throws for 27 yards. Even with Georgia selling out to stop the run in the second half, the secondary still only surrendered one passing play longer than 9 yards — a harmless 14-yarder to Tony Stevens — the entire day.

The Bulldogs were far from fabulous offensively, but they did shorten the game by possessing the ball for 39:09 to Auburn’s 20:51.

Nov 12, 2016; Athens, GA, USA; Auburn Tigers running back Kerryon Johnson (21) is tackled by Georgia Bulldogs linebacker Davin Bellamy (17) during the second quarter at Sanford Stadium. Mandatory Credit: Dale Zanine-USA TODAY Sports

Credit: Dale Zanine-USA TODAY Sports

While Pettway being scratched was key, Johnson is 10th in the league with 715 yards rushing. He was the starting tailback on The Plains before missing some time himself with injury. Only then did Pettway become a household name.

“We don’t game plan for a specific person,” Bellamy (above) told 247Sports. “We don’t do team run for Pettway on Tuesday and Wednesday. We do team run to stop the run so whoever is back there, that’s who we’ve got to be focused on. The way that we played (Saturday), you could have had anybody back there.”

UGA is now the No. 4 rushing defense in the SEC behind Alabama, Florida and LSU. It’s possible that ranking could move up to No. 2 by season’s end, as the Dawgs’ 119.1 yards per game allowed are only 7.8 behind the Gators’ 111.3 — nobody is catching the Crimson Tide and their nation’s-best mark of 68.8, of course.

“We finally put four quarters together,” Bellamy said, “and you guys saw what happened when we do that.”

When Smart got the job at his alma mater, the assumption was he wanted to build Tuscaloosa East following his apprenticeship under Nick Saban.

The one constant for ‘Bama during the Saban era has been its rushing defense. Amazingly, the Tide have finished No. 1 in the conference in that category every year since 2008. Only in 2010 did they slip to No. 2.

Georgia has now faced the first- and third-best rushing offense in the league the last two weeks — and emerged a winner both times. Kentucky, averaging 238.5 on the ground, was held to 186 at home back in Week 10. After saying goodbye to the Bulldogs, the Wildcats traveled to Tennessee and ran for 443, albeit in defeat.

UGA wasn’t a ready-made program when Smart returned to the site of his playing days. One box seems to have been checked, though.

John Crist is the senior writer for Saturday Down South, a member of the FWAA and a voter for the Heisman Trophy. Send him an e-mail, like him on Facebook or follow him on Twitter.