Weeden was 33 for 49 for 338 yards after a sizzling start. The 28-year-old senior was 19 for 25 for 214 yards in the first quarter, with all six incompletions on drops.
Michael Harrison was wide open on a 27-yard catch and Blackmon caught an 8-yarder for his 28th receiving touchdown in 19 games. On the first play of the second quarter, Oklahoma State went up 21-3 on Weeden's 13-yard TD pass to Randle.
A trick play produced Missouri's best play of the quarter, with Franklin throwing a lateral pass to Moe and then getting it back for a 31-yard gain to the 13. But the Tigers stalled, settling for a short field goal by Grant Ressel.