Auburn's defense has improved dramatically since the last time the Tigers faced Dak Prescott.

Then again, so has Prescott. That was long before the 6-foot-2, 230-pound star for No. 3 Mississippi State emerged as the Southeastern Conference's hottest quarterback and the biggest challenge the second-ranked Tigers have faced this season.

"This will be the first quarterback in a while with that size and caliber," Auburn cornerback Johnathon Mincy said.

Known more for offense, the Tigers (5-0, 2-0 SEC) have had one of the league's best defenses so far this season but have only faced two quarterbacks ranked in the Top 100 nationally in total offense.

A much truer test of Auburn's defense comes Saturday versus Prescott, who's ninth in that category and has produced three straight games with 200 passing yards and 100 rushing yards.

The first time Prescott managed that feat was last season against Auburn, in the second start of his college career and first against an FBS team.

The Tigers won on a touchdown pass from Nick Marshall to C.J. Uzomah in the final seconds.

Both Prescott and Auburn's defense have gotten better since then, and they'll leave Saturday's game with a clearer idea of just how far they've come.

An Auburn front line that is big and deep has to try to keep Prescott from bulldozing through, and he'll challenge a youthful secondary, too.

"He puts a tremendous amount of pressure on you," Auburn defensive tackle Gabe Wright said. "He is a dual-threat quarterback and just saying that, I think that in itself already speaks volumes. Dual-threat means he can both run and pass. And he's mentally capable to run their offense now. I think he's more comfortable now. "

Auburn went to last season's national championship game with a high-powered offense and a defense that came up big in some clutch situations while facing a Who's Who lineup up quarterbacks that included Heisman Trophy winners Johnny Manziel and Jameis Winston and 2013 runner-up AJ McCarron.

Now, the defenders are more than holding their own in the second season under coordinator Ellis Johnson against a lesser-known group of quarterbacks.

Auburn ranks among the league's top three teams in scoring, total and run defense. The Tigers, who are ninth nationally in scoring defense, have allowed 21 or fewer points for five straight games for the first time since doing it eight times in a row from 2007-08.

A bigger number for Johnson is the missed assignments. He said the Tigers were plagued with 25-30 a game this time last season and now are more likely in the 8-10 range.

Auburn doesn't have a dominant pass rusher like Dee Ford last year, but has started 300-pounders Gabe Wright and Montravius Adams both inside and out and has a nine-man rotation plus linebackers Kris Frost and Cassanova McKinzy. No opposing running back — or quarterback, for that matter — has gained 100 yards against Auburn this season. That includes Arkansas' Alex Collins (68 yards).

Auburn didn't allow dual-threat Kansas State quarterback Jake Waters any success running, though he passed for 245 yards.

The Tigers shut down young LSU quarterbacks Brandon Harris and Anthony Jennings last Saturday. But Prescott has thrust himself squarely into the early Heisman Trophy conversation with huge games against the SEC's LSU and Texas A&M.

"This week, we're going to be playing a quarterback who may be the best in the country at running the offense he runs," said Johnson, who was Mississippi State's defensive coordinator from 2004-07. "It's going to be a whole different deal. He's a veteran. He had about eight starts last year and he's playing really well this year and we're going to be playing at their place instead of our place.

"I'm certainly not taking anything away from the effort and the accomplishment of our players. I think we did a great job and I'm really proud of them, but the test is going to get a lot tougher."