The greatest comeback in 103 seasons of NFL football has to start with one pebble falling into place somewhere to start the unprecedented avalanche we all witnessed at U.S. Bank Stadium on Saturday.

Here's that one pebble that turned the Vikings' 33-0 halftime deficit into No. 3 receiver K.J. Osborn's spot-on Justin Jefferson impersonation and a 39-36 overtime victory over Indianapolis:

Colts linebacker Dayo Odeyingbo was standing over and taunting Vikings receiver Jalen Reagor after turning Reagor's jet sweep into a 5-yard loss.

"I couldn't hear what the guy said to me," Reagor said. "But I knew it wasn't good for the Colts."

No, it wasn't. What should have been second-and-15 from the Vikings 20 turned into first-and-10 from the Vikings 35. The Colts led 33-0 with what they presumed would be only 25 more minutes of garbage time.

"Maybe that was a break we needed, but hey, they sure called a lot of breaks the other way," said Osborn, referring to the officials robbing the Vikings of not one, but two fumble returns for touchdowns.

Two plays after the taunting penalty, the first giant boulder fell into place when Kirk Cousins spotted a mismatch and launched a 63-yard deep ball to Osborn.

"I knew it was just kind of me one-on-one with the linebacker and if I got over the top of him, it was going to be a big play," Osborn said. "I kind of stuck him, and Kirk saw the same thing I did."

Is that where the comeback started, K.J.?

"It could have been," he said. "I'm still trying to process this game. I'm in a daze. It was crazy. That was the spark we needed, and I'm happy I was able to do it."

Osborn had only two first-half catches for 16 yards on five targets, including a 40-yard catch that became an incompletion after a Colts challenge.

Osborn was targeted 11 times after halftime, catching eight passes for 141 yards and a 2-yard touchdown on third-and-goal that made it a 33-7 game three snaps after Osborn's 63-yarder. His career-high 157 receiving yards also was the first 100-yard game of his career.

"K.J.'s a guy that could do that every week, but you've got Justin, you have Adam [Thielen], T.J. [Hockenson], Dalvin [Cook], Alex [Alexander Mattison]," Cousins said. "It's been hard to get him the football as much as he deserves it and has shown the ability to deserve it. He's a guy that all season long I've kind of felt we need to get him more targets, get him more opportunities, because he's the real deal."

Indeed.

Osborn's eight catches after halftime produced six first downs and two third-down conversions. Two of the first downs came in overtime, including a 15-yarder on the game-winning drive.

Greg Joseph's 40-yard field goal sunk a Colts team that has been outscored 72-9 in the second half of its past two games, including the 54-19 loss to Dallas.

"It's the story of our season," said Colts defensive end Ifeadi Odenigbo, a former Vikings player. "We're up 33-0 at halftime and we go out and get a three-and-out to start the second half. Then things got weird and just kept getting weirder."

Yes, they did. The Vikings somehow won a game in which they were robbed of two touchdowns, had a punt blocked for a touchdown, turned the ball over on downs from their 31-yard line on back-to-back possessions, including a botched fake punt, and … well, you get the idea.

"Strange things happen in this building," said Odenigbo, who was on the practice squad of the 2017 Vikings team that performed the Minneapolis Miracle. "We were rolling and then the momentum and the building went against us."

It started with a simple taunting penalty, followed by a whole lot of great defense, big plays and a career day (so far) for K.J. Osborn.

"I told K.J. a few weeks back that his time was coming," coach Kevin O'Connell said. "I just knew it would happen. [What] I didn't necessarily envision is maybe the scenario that played out today."

Nobody did. Until it actually happened.