COLUMBIA, Mo. -- Missouri seemed to be caught up in the emotions of senior night Wednesday.

Its porous defense allowed a flurry of 3-pointers by Iowa State that had the seventh-ranked Tigers trailing for most of the game.

But when Missouri's Steve Moore dived to corral a rebound midway through the second half, it provided a spark the Tigers would capitalize on en route to a 78-72 victory that clinched the No. 2 seed in next week's Big 12 tournament.

Moore's pass found Michael Dixon, who then made a half-court pass to Kim English for an easy layup with 12 minutes, 12 seconds remaining that gave Missouri a 53-52 lead, its first since 8:50 left in the first half.

"I don't know if we were winning the effort game, and that play right there was a sign of us getting back to who we are," Missouri coach Frank Haith said. "And that was a hell of a play."

Dixon scored 21 points to lead five Missouri players in double figures.

Dixon's driving layup with 3:36 left gave Missouri (26-4, 13-4) a 66-64 lead it wouldn't relinquish. Marcus Denmon followed with a 3-pointer, and Phil Pressey had a steal and layup with 1:23 remaining to cap a 7-0 run for the Tigers.

It was Missouri's 13th Big 12 win, the most in school history, as it prepares to leave for the Southeastern Conference next season. Finishing in second place would be the Tigers' best regular-season performance since coach Norm Stewart's final season, 1998-99.

But Haith won't allow his team to look past the next game, insisting on maintaining the same "process" that's produced consistent success this season, his first at Missouri. But the team clearly looked relived after the game, with many seniors grabbing the stadium's microphone to thank their families.

Missouri entered the game on its first two-game losing streak of the season, including an emotional 87-86 overtime loss at No. 3 Kansas on Saturday.