BOULDER, Colo. (AP) -- Ben Kelly finished what he started, even if it did take four hours to get it done.

Kelly, who opened the game with a 100-yard kickoff return, concluded it with an interception at the goal line in overtime, preserving Colorado's wild 46-39 victory over Missouri on Saturday.

Mike Moschetti threw a 24-yard touchdown pass to Marcus Stiggers on Colorado's possession in overtime, and Kelly thwarted Missouri moments later, picking off a pass from Kirk Farmer intended for Eric Spencer.

"What an emotional roller-coaster!" Colorado coach Gary Barnett said. "To go for the lead the way we did, give it away, go for the lead, give it away -- that game had just about everything you've seen in a college football game."

Missouri coach Larry Smith agreed.

"I just thought it was a heck of a football game," he said. "We got down by two touchdowns at the end, but our team really showed their colors and fought back hard and took it into overtime. Colorado just made more plays at critical times. They made plays in the kicking game and got turnovers, and that's what basically cost us the game."

In the longest game in Colorado history -- exactly four hours -- and the school's first overtime game, Colorado (3-2, 2-0 Big 12) rallied from a 25-18 deficit with three straight fourth-quarter touchdowns. Interceptions by Brady McDonnell and Damen Wheeler accounted for two of the scores, helping the Buffaloes take a 39-25 lead with 4:12 left.

But Farmer, a redshirt freshman, sparked Missouri to two touchdowns and a 39-39 tie at the end of regulation. Farmer completed a 55-yard pass to Kent Layman and then scrambled 21 yards for a TD, cutting the deficit to 39-32 with 3:04 remaining.

The Tigers (3-2, 0-2) then recovered an onside kick, and Farmer's 27-yard pass to Spencer with 1:42 left produced the tie.

Colorado drove to the Missouri 35 in the waning seconds, but Jeremy Aldrich was wide on a 53-yard field goal attempt with 13 seconds to go.

Missouri won the coin toss to begin overtime and elected to go on defense. On the second play, Moschetti, facing pressure up the middle from linebacker Jamonte Robinson, hit Stiggers in the rear of the end zone.

After four plays on Missouri's first possession of overtime, the Tigers faced a fourth-and-12 from the Colorado 17. Kelly, who had dumped DeVaughn Black for a 3-yard loss on third down, picked off Farmer's pass on the right side.

"They were in a fourth-and-long and had to get to the 5-yard line," Kelly said. "Knowing that, I just read the quarterback's eyes. We were in a zone. I backed off the receiver and read the ball the whole way."

Moschetti said a loss would have been devastating to his team.

"If we would have lost this game, it would have been tough the rest of the season," he said. "It came down to making plays, and today we made some. Hopefully, this game will be the catalyst for the rest of our season."

Barnett said the game came down to "one team wanting it a little bit more. I just think we played with heart."

Colorado, which squandered an early 13-0 lead, trailed 17-16 at halftime but took an 18-17 lead early in the third quarter on the second safety of the game.

Missouri, now 3-2 in overtime games, reclaimed the lead after a blocked punt by Julian Jones and Barry Odoms' 5-yard return to the Colorado 16. Freshman fullback Joe Chirumbolo, who earlier scored on a 20-yard run, caught Farmer's 16-yard TD pass for a 25-18 lead with 3:03 left in the third period.

Early in the fourth quarter, the Buffs began an 80-yard scoring drive that culminated in Moschetti's 1-yard sneak with 7:01 to go. The drive was kept alive on a roughing-the-passer penalty against

Justin Smith and a fake field goal, on which holder Nick Pietsch passed 7 yards to a diving Daniel Graham for a first down at the 1.

Two plays later, McDonnell, a defensive end, intercepted a short pass and returned it 24 yards to the 1-yard line. Moschetti scored on the next play.

Six plays after that, Wheeler picked off Farmer and returned it 37 yards for another score and a 39-25 lead.

The three scores came in a span of 2:49, but Missouri then got two scores just 1:22 apart.