The top scoring defense in college football currently resides in the SEC, but it’s not the one you think.

Alabama has allowed the fewest points per game in the country three times during coach Nick Saban’s tenure, including this past season. But the Crimson Tide have now given up 13.3 through three games, which is tied for 16th nationally.

Vanderbilt, on the other hand, is surrendering just 4.3 points per contest to lead the nation. Middle Tennessee only scored 6 points in Week 1, Alabama A&M was shut out in Week 2 and Kansas State could do no better than 7 — the Wildcats had scored a whopping 110 combined in their first two contests, both lopsided victories — in Week 3.

Even with the departure of linebacker Zach Cunningham, who did almost everything last year, Commodores coach Derek Mason is pushing all the right buttons.

He calls his own defensive signals, which is somewhat rare in today’s landscape. While Missouri coach Barry Odom also pulls double duty, he hasn’t had much success. But Mason has thrived in that role and earned the respect of his peers.

In 2016, Vandy was sixth in total defense in the conference and fifth in scoring defense. Mason’s squad didn’t rush the quarterback consistently or pick off enough passes — the ‘Dores finished dead last in sacks and interceptions by healthy margins. Granted, it’s still early, but they’re currently tied for the league lead in both categories.

Mason and Co. will face their toughest task to date, as the top-ranked Crimson Tide roll into Nashville in Week 4.

“I think this is, all the way around, an outstanding defensive team,” Saban said Wednesday on the SEC’s weekly coaches teleconference. “I think it starts up front with them. They’re very impressive. They’ve got good speed. Their linebackers are very active and quick to jump over. They attack out front. This will be a real challenge for our offensive line. They swim. They move. They do a lot of things. They’ve got pretty good quickness. They run well. So this is a very athletic defensive team, and they know their scheme well. They don’t make very many mental errors.”

'Bama QB Jalen Hurts is an even more dangerous dual threat and has back-to-back 100-yard games.

Vanderbilt has been exceptional thus far defending the pass, as its 95.3 yards per game allowed through the air is first in the SEC. Only once in three outings has an opponent completed a pass for a gain of 30 or more yards.

It’s a different story on the ground, though. The Commodores are a middle-of-the-road unit in the conference against the run. In particular, KSU quarterback Jess Ertz ran for 126 yards — to be fair, it took him 24 carries to get there — in a losing effort. ‘Bama QB Jalen Hurts is an even more dangerous dual threat and has back-to-back 100-yard games.

Hurts can make any defense pay with the way he turns the corner so quickly, although Vandy tends to be quite disciplined.

“I think they’ve got a really good team,” Saban said. “They play well. They’re really well coached. They play hard, physical, tough. They’ve got very good schemes on offense and defense and special teams. So when you watch the film, you see a really good team that’s really well coached. And I think Derek deserves a lot of credit for that.”

Credit: Marvin Gentry-USA TODAY Sports

Even if Hurts (above) is still more effective with his legs than his arm, he appears to have made some progress as a passer. He’s presently hitting on 67.9 percent of his throws with a perfect touchdown-to-interception ratio of 4-to-0.

Pressure affects every signal caller, even the high-speed ones like Hurts, so Vandy must maximize it new-found ability to collapse the pocket. Linebacker Charles Wright is second in America with 6.0 sacks — he only had 1.0 as a collegian prior to this season — and has been one of the league’s breakout stars in the early part of the schedule.

"Pass rush and coverage work together. But what a lot of people don't realize is that in each of the last two years, we missed double digits. I mean, we were in the twenties in terms of missed opportunities. If you catch the ones that come to you, you're going to lead the country." -- Derek Mason

And he isn’t doing it alone, as defensive end Dare Odeyingbo has 2.5. Like Wright, he came into 2017 with 1.0 career sack.

“It’s a different team with different guys that are capable of getting to the passer,” Mason said. “We’ve got better pass rushers than we had a year ago. Some of it’s age and experience, and some of it is youth.”

The Tide lost ArDarius Stewart and O.J. Howard to the NFL Draft, and nobody else has truly stepped up yet opposite primary receiver Calvin Ridley. He has 15 catches, which equals the total output of all the other wideouts and tight ends on the roster.

Still, Hurts is yet to be intercepted. The ‘Dores have shown much stickier hands so far this year, as five different defenders have picked off a pass already — this D recorded only 5 INTs all of last season. Of course, it’s assumed that the improved pass rush has given the defensive backfield more shots to break on the ball.

But as Mason sees it, they aren’t necessarily getting extra chances for takeaways. They’re just making all the plays that were previously left on the table.

“Pass rush and coverage work together,” he said. “But what a lot of people don’t realize is that in each of the last two years, we missed double digits. I mean, we were in the twenties in terms of missed opportunities. If you catch the ones that come to you, you’re going to lead the country.”

Vanderbilt has been one of the pleasant surprises in the SEC. Georgia looks beatable. Florida and Tennessee haven’t been impressive. Kentucky and South Carolina are, well, Kentucky and South Carolina. The East is as wide open as it gets.

We’ll find out Saturday if the Commodores are contenders or pretenders. While they don’t necessarily need to upset Alabama — they’re 18.5-point underdogs in Las Vegas — keeping it close would signal to the rest of the division that they’re for real. After all, the Crimson Tide haven’t lost to a team from the East since 2010.

If Mason’s defense keeps playing like this, then Vandy has a chance. A very small chance, let’s be honest, but a chance indeed.