Williams had a season-high 16 points and Texas avenged a 65-62 loss at Tech on Jan. 10.
"I felt better today than I have in a long time. My knees felt good and in pre-game, I just felt great. I was ready to play," Williams said.
She keyed the 31-point victory that was Texas' largest margin against Tech in 19 years.
"We have been waiting for "Earnie" to have this kind of game all season. She works so hard at practice that she deserved to have the opportunity to have this kind of game, said Texas coach Gail Goestenkors.
Erika Arriaran scored 11 points and Kathleen Nash added 10 for Texas (17-5, 5-3).
Texas outscored Texas Tech 29-9 over the final 8:39 of the first half to take control of the game. The teams were tied at 16 when Tech senior Dominic Seals went to the bench with her second foul. The Longhorns went on an 11-0 run over 2:33 with Seals out.
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She returned, but quickly picked up her third foul and the Longhorns outscored Tech 18-9 to take a 45-25 halftime lead.
Tech staged a 9-0 run to open the second half, but Texas answered with a 16-2 run that put the game away.
Mari Moore led Tech (13-9, 3-5) with 15 points. Jordan Murphree added 12.
"They were cutting in to the basket and we failed to get back into the lanes on defense," Murphree said.
"We are playing much better than we did early in the year," Goestenkors said. "We have high energy, better focus. We got great effort off the bench today and every player was ready to produce when she got into the game."
Texas got a 38-5 scoring edge off the bench and outscored the Red Raiders 40-22 in the paint.
"Our freshmen aren't freshmen anymore. They are playing well and our veterans are really playing with high energy," Goestenkors said.
Texas had a 41-33 edge in rebounding and managed 26 points off Tech turnovers.
"We work rebounding very hard," said Kathleen Nash, who had seven of the team's rebounds. "Coach says whichever team wins the boards will usually win the game, so we really worked hard today."