Kansas guard Darryn Peterson (22) watches from the bench during the second half on Saturday, Jan. 31, 2026 at Allen Fieldhouse. Photo by Nick Krug

Kansas needed every ounce of energy it could possibly muster to take down No. 13 BYU 90-82 on Saturday afternoon.

The problem was that it had already expended a great deal of its energy reserves in the first half before a rocking Allen Fieldhouse crowd — as good an atmosphere as head coach Bill Self could remember in the building, he said — on its way to a big halftime lead.

So it was perhaps a predictable development that KU ran out of gas with about nine minutes remaining — and fortunate for the Jayhawks that they were still up 18 at that point.

“We were exhausted on both ends,” Self said. “That’s as tired as I’ve seen Flory (Bidunga) and Melvin (Council Jr.) and Mari (McDowell). We were exhausted. There was so much energy the first half, it was almost like you run on adrenaline so long, and then the adrenaline ran out and it switched jerseys. We were a tired team just trying to get to the finish line, and we had no depth.”

The lack of depth arose from factors beyond the Jayhawks’ control.

One such factor was a first-half injury to guard Elmarko Jackson, one of KU’s best defenders and an occasional X-factor on offense, when he got tangled up with BYU star AJ Dybantsa and was called for a foul at the 10:27 mark. That kept him out of the remainder of the game.

“He got it bumped,” Self said. “He’s had that injury (torn patellar tendon in the summer of 2024), and he’s done so good coming back. Today’s the best he’s felt, he said. He just got a bump when he and AJ tripped there in the first half.”

The other was a brutal recurrence of star guard Darryn Peterson’s cramping issues that ended up keeping him out for most of the second half — Self said he didn’t know why they affected Peterson so much earlier than usual.

“I’m not a doctor,” Self said, “but he definitely started cramping.”

The result was the highest minute total for the rotational wing McDowell since Dec. 2 (26 minutes), as well as a brief appearance by Jayden Dawson as KU essentially had to cut its rotation to six players.

It is not necessarily an opportune time, in short, for the Jayhawks to face a quick turnaround between games — and yet they must trek down to United Supermarkets Arena to face Texas Tech for a Big Monday battle at 8 p.m. It hasn’t been an easy place for KU teams to play in recent years, most notably in a 79-50 blowout loss in 2024.

“This is what we came to Kansas for, for games like this,” Council said. “Just next game up, we just got to practice tomorrow, have a good practice, and we should be good.”

It may not be all that much of a practice on Sunday. Self said it could be a walkthrough day as the Jayhawks attempt to “play Monday without really trying to expend any energy between now and then.”

The high-flying Red Raiders, for their part, suffered just their second loss of conference play on Saturday afternoon.

“I’m sure Grant (McCasland) will have their full attention,” Self said. “Now, we got to make sure that we have our guys’ full attention on a gas tank that’s running pretty low right now.”

Tech’s loss came at the hands of upstart UCF, which beat Texas Tech 88-80 at Addition Financial Arena.

The Red Raiders’ elite forward JT Toppin, the Big 12’s preseason player of the year, put up an efficient 27-point, 10-rebound double-double, and point guard Christian Anderson posted 17 points and nine assists, but Tech didn’t get a lot out of its supporting cast, committed 13 turnovers while forcing just six and got outrebounded 35-23.

Some of those developments were unusual for what had been one of the hottest teams in the Big 12. The Red Raiders have a mid-level scoring defense but have stolen the ball just 35 times in eight league games. Generally, though, they perform well on the boards with one of the league’s top rebounding margins, led by Toppin, whose 11.3 boards lead all players in league games.

One constant for Tech — and one KU experienced firsthand in a 78-73 home loss last March — is its 3-point shooting. The Red Raiders rank in the national top 10 in 3-pointers made per game, led by Anderson (19.6 points, 7.5 assists, 43.6% from beyond the arc) and Atwell, a 6-foot-5 guard who transferred from UNC Greensboro (12.1 points, 44.2% from beyond the arc).

Joining Toppin and the hot-shooting guards in KU’s lineup are 6-foot-6 LeJuan Watts, a highly touted Washington State transfer averaging 12.7 points and 6.2 rebounds whose scoring output has been a bit inconsistent, and freshman guard Jaylen Petty.

“We got to guard the short roll, and we got to guard Anderson,” Self said. “So we’ll try to figure something out to maybe give us a better chance.”

A positive sign for the Jayhawks: Self said he expects both Jackson and Peterson will likely be able to return on Monday, noting that Jackson’s “tests were even better after the game than what they were at halftime.”

How long Peterson is able to play during the game in Lubbock, of course, may be much harder to predict if recent appearances are any indication.

“We can be competitive,” Self said, “but for us to have a chance to actually do anything that I would consider to be (a) special type of deal, we need everybody healthy.”