One down, two to go.

No. 10 Auburn took a huge step forward in its Playoff quest, dominating No. 1 Georgia 40-17 Saturday at Jordan-Hare Stadium.

It was Auburn’s first victory over a No. 1-ranked team since beating Alabama on Chris Davis’ Kick-Six in 2013. And it set up an Iron Bowl date in two weeks that not only will decide the SEC West but likely a Playoff spot.

Auburn’s path to the Playoff is as simple on paper as it is difficult on turf: sweep Georgia, Alabama and Georgia again in the SEC Championship Game on Dec. 2.

The Tigers emphatically cleared the first hurdle, thanks to equal parts Jarrett Stidham, Kerryon Johnson and a dominant defense that muted Georgia’s rush game and forced true freshman Jake Fromm to beat them.

All season, many have wondered, rightfully, whether Fromm could win a game when tested. He wasn’t tested often throughout the Bulldogs’ 9-0 start. He was under attack all afternoon Saturday.

He missed on two big throws that could have produced points. Though the score looked lopsided, those early misses, and Georgia’s numerous penalties, compounded their problem.

Stidham, his counterpart, was nearly flawless. He came to Auburn to win games like this. What he did Saturday was set the table for even bigger moments.

He closed the second quarter with a 42-yard strike for a touchdown and put the game out of reach with a 32-yard bubble screen to Ryan Davis, who weaved through traffic to find the end zone and extend Auburn’s lead to 30-7 midway through the third. He added a third touchdown pass to Johnson.

Auburn’s defense did the rest, dominating after the opening drive in which Georgia went 70 yards in eight crisp plays on its opening possession for a 7-0 lead.

Fromm hit Javon Wims for 28 yards and Terry Godwin for 26 yards on back-to-back plays to quickly move to Auburn’s 13. Georgia’s run game took over from there, finishing with Nick Chubb’s 1-yard touchdown.

Georgia faced just one third down on that drive, and Fromm converted that on the strike to Wims. It was an outlier, fool’s gold that a team that pounded the SEC East could do so against the SEC West.

Auburn’s defense tightened considerably afterward, forcing punts on the Bulldogs’ next six possessions and allowing its offense the opportunity to assert itself.

Daniel Carlson’s third field goal gave Auburn its first lead at 9-7, and after Auburn forced another three-and-out, Auburn drove 70 yards on six plays for its first touchdown.

That drive was aided by a Georgia penalty on fourth down. Given a second chance, Stidham finally took a shot over the Dawgs, hitting Darius Slayton on a post pattern between two defenders for a 42-yard touchdown and 16-7 advantage.

Georgia trailed at halftime for the second time this season, and the 9-point margin was the biggest it had faced all season.

Auburn had been in this position before. It let a 20-point lead slip away at LSU.

It failed to score in the second half of its only two losses — at Clemson and at LSU.

Johnson, of course, didn’t play at Clemson. He made play after play Saturday. Already the SEC’s leading rusher, he added 167 more yards to his total, going over the 1,000-yard mark in the process. All of that came before he sealed his signature night with a 55-yard touchdown reception to make it 40-10.

Saturday, the Tigers put the hammer down and shifted gears as they raced into the Playoff conversation.

They’re rolling into the Iron Bowl, final destination to be determined.

Georgia looked overmatched and overwhelmed, but the Dawgs aren’t done. They’re already headed to Atlanta, where they might earn a rematch, and still might earn a Playoff spot if it wins the SEC title. But it’s worth noting that no Playoff team has suffered a regular-season loss by more than 14 points.

Both teams entered the Deep South’s Oldest Rivalry with Playoff aspirations, but as the sun set on The Plains, one team looked clearly looked the part much more than the other.