It wasn't just the Longhorns' defense against Alan Voskuil, Texas Tech's leading scorer, that improved after halftime.
"We did a better job too of taking care of the ball," Barnes said. "I think we only had three turnovers in the second half. Two of those came in the last minute-and-a-half."
Damion James scored 14 of his 18 points in the second half for the Longhorns.
"We consider ourselves the big-time players," said James who was 6-of-14 from the field. "We want to make plays. We were able to do that today. Got a lot of movement. That allowed us to go in and get a lot of offensive rebounds."
Gary Johnson and Justin Mason added 15 points each for the Longhorns (13-4, 2-1 Big 12). Mason had 10 rebounds, tying his career high and getting his first career double-double.
Johnson carried Texas in the first half, and James and Mason picked up their play to lead the Longhorns in the second with Mason scoring 12 points over the final 20 minutes.
Voskuil scored 12 points and Mike Singletary added 10 for the Red Raiders (10-7, 0-2).
Texas used a 12-4 run to go ahead 54-36 with 12:31 remaining and Texas Tech didn't threaten from there.
It was the second straight season Texas Tech coach Pat Knight opened 0-2 in the conference.
The loss kept Knight from getting consecutive home wins over the Longhorns. Texas Tech beat then-No. 5 Texas 83-80 in Lubbock last year, less than a month after Bob Knight resigned and turned the program over to his son.
Tech shot just 34 percent from the field (18-of-53).
Knight was frustrated with his team's shooting percentage.
"I wish this team had my personality. We don't compete right now," he said. "I have no idea why we shot so poorly. If I knew, we wouldn't be shooting poorly."
At one point a Red Raiders fan screamed out "39-33" -- the score of the Texas Tech-Texas football game in November when a last-second touchdown gave the Red Raiders the win over then-No.1 Texas. But there was no upset for Texas Tech on Saturday.
At one time, though, it did look a bit like football.
A Texas Tech player lost control of the ball on offense and several players from both teams had chances to gain control. Finally, Nick Okorie came away from the scrum with the ball and made an easy layup to whittle the Red Raiders' deficit to 47-36.
Texas players went to the basket consistently, getting 30 points in the paint, and went to the line 20 times, making all but five. Tech only got to the free throw line 13 times, making six.
Tech went up early but a 7-minute drought allowed the Longhorns to pull ahead for good in the first half. The Red Raiders' scoreless spell ended on a 3-pointer by Voskuil with 10:27 remaining in the half to make it 14-11.
Barnes knew his team would have to watch Voskuil.
"Tech does a great job of screen and re-screen and he reads it well and he doesn't need much separation to get things done," Barnes said
Texas led 30-24 at halftime.
Tech's points were its lowest in a first half and a game this season.