WACO, Texas - Those early hard lessons on the road are really starting to pay off for Kansas.

The defending national champion Jayhawks, who had to go through some growing pains without any returning starters, are still undefeated in the Big 12 nearly halfway through their conference schedule after winning 75-65 at Baylor on Monday night.

“Our guys played older tonight,” coach Bill Self said. “We played like a pretty poised team for the most part.”

No. 21 Kansas, ranked for the first time in eight weeks, finally grabbed the lead in the final minute of the first half. Freshman Marcus Morris then had a dominating start after halftime before his twin brother, Markieff, also added some big contributions.

The Jayhawks (18-4, 7-0) moved into the Top 25 on Monday for the first time since early December. They responded by remaining undefeated in the Big 12, along with No. 2 Oklahoma (21-1, 7-0), and have won all four conference road games.

“This just shows the potential we’ve got,” Sherrod Collins said. “We’re learning and everybody is buying into Coach’s system and we’re just finding out where we are and getting better day-by-day.”

Kansas, which began the season No. 24 and peaked at 22 before Thanksgiving before double-digit losses at Arizona and Michigan State in their only true non-conference road games. There was also a blown double-digit lead against Syracuse that became an overtime loss.

Marcus Morris scored the Jayhawks’ first eight points after halftime. When Markieff Morris hit an open 3-pointer from the top of the key with 15:56 left, the Jayhawks led 43-33.

“I needed to be more aggressive. Coach told me that when I got the ball that they couldn’t really guard me,” Marcus Morris said. “He said try to be aggressive as you can coming out to set the tempo for the second half.”

Collins had 17 points, and has led Kansas in scoring in all but five games this season. Marcus Morris had a season-high 13 points and Mario Little had 12.

Henry Dugat and Kevin Rogers had 15 points each to lead four players in double figures for Baylor (15-7, 3-5), which has lost four straight games.

When LaceDarius Dunn drove for a layup with 8 minutes left that appeared to get Baylor within a basket, Markieff Morris had instead drawn a charging foul to wipe out the score.

Markieff then had a putback basket on the next possession to make it 58-52. He blocked a shot and eventually stretched the lead back to 66-55 by capping a wild scramble under the Kansas basket when, while falling down, he got a pass to an open Little inside for a basket.

Baylor opened the second half with a turnover, and Marcus Morris scored a basket. He turned it over on a traveling call, but then scored despite being hit in the face. After he stole a pass, he finished the break with a tip-in of Collins’ miss. And Morris then took a pass inside for another score to make it 38-33.

“That takes the load off everybody else and draws him attention,” Collins said. “People worry about him and it opens things up for everybody else. I think it was big for him to play real big for us.”

The Bears, whose only win in the 15-game series was in a Monday night home feature game eight years ago, closed within 48-47 after consecutive 3-pointers by Tweety Carter. That was part of a 12-2 run over 3 minutes when Dunn made a 3-pointer and Dugat made three free throws after being fouled beyond the arc.

“When you get close like that, it gets tough if you never get over the hump,” coach Scott Drew said. “You lose steam, lose some momentum. … You take the lead, it’s a much different game.”

But Baylor never got closer, with Collins hitting a basket before Markieff Morris’ contributing stretch.

Dunn had 13 points and Carter 12 for Baylor. Curtis Jerrells, the Bears’ leading scorer, was held to a season-low four points on free throws. Jerrells was 0-for-7 shooting after going 2-for-10 with five points against Missouri on Saturday.

Kansas led 30-28 at halftime after Collins dribbled into the lane for a short floater that dropped in as time expired. The Jayhawks led once before that, on Collins’ jumper the previous possession before Dugat hit two free throws with 7.8 seconds left.

Then, the Jayhawks took over after halftime.

“That was probably the best half of basketball we played all year,” Self said.