COLUMBIA, Mo. (AP) - It hasn't always been easy this season for Missouri wide receiver Jerrell Jackson, and coaches have let him know about his mistakes. But now, the sophomore has emerged as a legitimate No. 2 receiver behind senior Danario Alexander.

Jackson's breakout game was Saturday in Missouri's 34-24 win over Iowa State. The game was a microcosm of his season. He had 39 receiving yards in the first half but also a drop and a critical fumble at the Iowa State 45. But in the second half, Jackson had four catches for 96 yards, including a 70-yard touchdown pass from Blaine Gabbert.

Jackson's eight catches for 142 yards were both career highs.

"Most people would be down after the first half I had, but coming in at halftime, the leaders came and talked to me and told me to keep my head up the whole time and I was ready to go back out there," Jackson said.

Earlier this month, Missouri (7-4, 3-4 Big 12) lost senior wide receiver Jared Perry, who injured his right tibia in the second quarter of a 38-12 win over Kansas State. He could return for a bowl game. Perry had 46 receptions for 696 yards and six touchdowns.

With Perry gone, the Tigers badly needed Jackson to emerge, and hope to get another big game from him Saturday in the regular-season finale against rival Kansas (5-6, 1-6) in Kansas City.

"Certainly we need him," coach Pinkel said. "With Perry out, he's the guy to step up at a higher level."

Jackson had just 15 catches for 148 yards through eight games, numbers he called disappointing.

The worst came in an Oct. 17 loss at Oklahoma State, where Jackson let a key pass bounce off his hands and into the arms of Cowboys defender Lucien Antoine, who ran 26 yards for a touchdown.

"I was really upset at myself after that but you have to make mistakes to get better," Jackson said. "I learned from that and just practiced looking the ball in for the rest of the season after that play."

Coaches also kept at Jackson.

"We've really coached him hard because you kind of saw flashes throughout spring and summer of what he has the ability to do," offensive coordinator Dave Yost said.

Things didn't get better immediately - Jackson had three total catches in a loss to Texas and win at Colorado. That's when Pinkel stepped in.

"After the Colorado game I came up to him afterwards and patted him on the back," Pinkel said. "In a very positive way I said, 'Good game, but you can be a lot better."'

Jackson responded with three catches in a home loss to Baylor, then six catches for 78 yards and three carries for 24 yards against Kansas State.

In addition to responding to coaching, Jackson has turned to the power of positive thinking, something he learned in his sports psychology class taught by Missouri track and field coach Rick McGuire.

"When I know plays are coming my way I think to myself, 'I'm going to make a big play, I'm going to get big yards. I'm going to catch this ball,"' Jackson said.

Teammates are now thinking positively about Jackson, too. "He's a tremendous talent," Gabbert said. "He's finally coming into his own as a player and he really stepped up last week."

(Copyright 2009 by The Associated Press. All Rights Reserved.)

AP-NY-11-25-09 1228EST