Maclin scored three touchdowns and had 252 total yards to set the NCAA single-season freshman record for all-purpose yards, helping the No. 6 Tigers rally from a sluggish first half for a 49-32 victory over Kansas State on Saturday.
Maclin returned a kickoff 99 yards for a touchdown and caught two touchdown passes, giving him 2,201 all-purpose yards for the season - 175 more than Terrell Willis of Rutgers had in 1993. Maclin finished with nine catches for 143 yards.
Chase Daniel threw for 284 yards and four touchdowns, including two to tight end Martin Rucker, helping Missouri (10-1, 6-1 Big 12) to its first win in Manhattan since 1989.
The Tigers entered the weekend ranked fifth in the BCS, needing wins over Kansas State (5-6, 3-5) and rival Kansas, No. 3 in the BCS, to remain in the national championship hunt.
The game against the Jayhawks next Saturday at Arrowhead Stadium in Kansas City, Mo., has been billed as the biggest in the history of the border rivalry - provided both teams beat unranked opponents on Saturday.
The Tigers almost didn't keep their end of the bargain, struggling offensively and allowing a blocked punt return for a touchdown in a tighter-than-expected first half.
But Missouri pulled away early in the third quarter, turning a 21-18 lead into a rout. The victory secured the second 10-win season in Missouri's 117-year history - first since 1960 - and gave the Tigers six conference wins for the first time since 1969.
Missouri figures to move up at least one spot in the BCS after No. 2 Oregon lost to Arizona on Thursday night, setting up one of this season's biggest college football games next week.
Maclin made sure the Tigers got there.
The redshirt freshman caught an 8-yard TD pass 67 seconds into the game, making a sliding grab in the end zone two plays after William Moore intercepted Josh Freeman's second pass. Maclin then followed Brooks Rossman's 18-yard field goal by breaking two tackles and streaking down the sideline for a 99-yard touchdown on the ensuing kickoff.
It was Missouri's first kick return for a touchdown since Ricky Doby scored on a reverse against Oklahoma State in 1982, the nation's longest drought.
Maclin put the game all but out of reach midway through the third quarter, somehow sneaking up the middle unnoticed for a 44-yard touchdown catch that put Missouri up 35-18.
Kansas State made it tougher than the Tigers would have liked, at least in the first half.
James Johnson ran for 172 yards - 119 in the first quarter - and Freeman passed for 243 yards, giving him 3,097 for the season, 253 more than Michael Bishop's Kansas State single-season record set in 1998.
But what kept the Wildcats close, at least in the first half, was defense. Kansas State allowed one sustained drive and held Missouri, which averaged 514 total yards through nine games, to 145 in the first 30 minutes.
Missouri led 21-18 at halftime, but it wasn't because of the defense: One score came on Maclin's kick return and another, Maclin's 8-yard catch from Daniel, came after an interception at the Kansas State 15 on the third play of the game.
But the Wildcats couldn't sustain the pressure in the second half, allowing four touchdowns in their third straight loss.