Ole Miss gained just 326 yards, most of that in a frantic fourth quarter rally. Two touchdowns in the final period weren't enough, and Mississippi State - with Diaz as the Bulldogs' one-year defensive coordinator - punctuated Houston Nutt's first losing season with a 31-23 win against the Rebels.
That was the first of two dismal seasons for Nutt, the beginning of a 14-game SEC losing streak. Ole Miss players believe they've turned a corner with new coach Hugh Freeze, and Diaz said he sees a different energy from the Rebels.
"They're a team that's not carrying the past around with them," Diaz said. "They're playing fast, playing free, playing hard, and they're extremely aggressive on both sides of the ball."
The Diaz defense held the Rebels to 1.9 yards per rush and 3 for 17 third-down efficiency.
For his part, Freeze has carried the past some - at least to the video room - to refresh himself on what a Diaz-coached unit looks like.
Statistically it looks pretty good. The Longhorns are coming off a 45-0 win over New Mexico. They defeated Wyoming 37-17 in the season opener and presently rank No. 27 in total defense, No. 8 in scoring defense.
Freeze watched the Diaz defenses at Mississippi State and Middle Tennessee as well.
Diaz led a top-50 defense at Middle Tennessee, a unit that ranked 24th nationally and first in the Sun Belt in pass defense efficiency.
In 2010 when Diaz helped the Bulldogs win in Oxford, Freeze was offensive coordinator at Arkansas State and led the Red Wolves to 51 points and 493 yards against Middle Tennessee.
Freeze's video study showed him that Diaz has adapted to the benefits of size and speed.
"He probably plays more man now at Texas than he did at Middle Tennessee," Freeze said. "That probably has to do with the fact that he has some of the best corners and skill guys in the nation on his football team."
A Longhorns defense that has been described as "bend but don't break" ranks No. 65 in run defense, No. 36 in pass defense efficiency.
Texas' success is based in large part on risk-taking.
Ole Miss quarterback Bo Wallace has completed 76.8 percent of his pass attempts in two games. The Longhorns' speed will give him less time to make right reads, and the Rebels' offensive line - which protected better in Week 2 than in Week 1 - will have to be assignment-sound.
Wallace won't be the only guy on the field who has to make snap calls on what the other guys are doing. Diaz says it works both ways.
"Everything they do is disguised very well formationally," he said. "They're always hunting the big-chunk play. They're a very, very good football team."