In hindsight, David Simmet admits he could have made a wiser wardrobe choice for his first meeting with St. Thomas football coach Glenn Caruso. “I was wearing a Johnnies shirt,’’ the Tommies offensive lineman said. “He didn’t hold it against me, thank God.’’

Simmet began life on the red side of this longstanding collegiate conflict by virtue of parentage; his father, Bob, played basketball for St. John’s. Saturday, he will line up on the purple side as the Tommies and Johnnies break new ground in a 114-year-old rivalry. The two Division III powerhouses will square off in the second round of the NCAA playoffs at O’Shaughnessy Stadium, the first time they have met in the postseason since their inaugural game on Thanksgiving Day in 1901.

The fourth-ranked Tommies currently hold the upper hand, having dealt the No. 10 Johnnies a 35-14 loss — their only defeat this season — on Sept. 26. Both sides said that game feels like ancient history as their programs prepare to face each other for the 85th time. The 11-0 Tommies are averaging 56.5 points per game, best of any team in all college divisions, while 10-1 St. John’s has become a more balanced and confident group that has outscored its past five opponents 219-28.

Off the field, the rivalry occasionally veers into Hatfield-McCoy territory, with alumni indulging in overheated chest-thumping and students chanting slogans not usually heard at Catholic universities. Those in uniform characterized it as more brotherly than bitter; many have friends across the line of scrimmage, guys they want to hang out with after their emotionally charged, hard-fought games.

With students on holiday break and a predicted temperature of 34 degrees, St. Thomas officials don’t expect the crowds of 10,000-plus that showed up for the past two home games against St. John’s. But Tommies-Johnnies: The Sequel, as it’s being billed, could be one of the most memorable chapters yet.

“I can’t wait,’’ St. John’s quarterback Nick Martin said. “I don’t think I could be more excited. St. Thomas is one of the best teams in the country, but I think we are, too.

“We have a chip on our shoulder. We’re looking forward to showing the Tommies we’re a different team than they faced in the fourth game of the year. It’s going to be a big event, for sure.’’

Two short months ago

Saturday’s big event comes two months after another milestone in the series. The teams’ regular-season game drew 17,327 to Clemens Stadium in Collegeville, the largest announced attendance in Division III history, and ESPN’s “SportsCenter on the Road’’ did a live broadcast from the stadium.

The rematch features two of the 10 semifinalists for the Division III player of the year award: the 6-9, 350-pound Simmet, who anchors the Tommies’ behemoth offensive line, and Johnnies running back Sam Sura, the school’s all-time leading rusher with 3,977 career yards. Both teams demolished their first-round playoff opponents last week, with St. Thomas beating La Verne 57-14 and St. John’s rolling past Dubuque 51-7.

Martin said the Tommies outmuscled the Johnnies in that Sept. 26 game, forcing his team to re-evaluate itself. It has grown steadily stronger since. Sura is averaging 142 yards per game, and Martin has become one of the nation’s most efficient passers, with 1,234 yards, 17 touchdowns and no interceptions during the Johnnies’ current seven-game win streak.

Tommies ‘hit a different gear’

Johnnies coach Gary Fasching said he saw no flaws in the Tommies two months ago, and he anticipates they have improved, too. An offense powered by running back Jordan Roberts and quarterback John Gould has scored a school-record 621 points, while the defense has allowed the third-fewest total yards (212.5 per game) and fourth-fewest points (8.6 per game) in Division III.

“That [victory at St. John’s] was a wonderful game for us,’’ Tommies coach Glenn Caruso said. “But since then, our program has really hit a different gear. Through the season, we’ve gotten faster and stronger.’’

Caruso said the rivalry has risen to a higher level, too. He fielded his first question about the Johnnies during his introductory news conference eight years ago; since then, he said, the series “has taken on a life of its own,’’ and the first Tommies-Johnnies playoff game is likely to magnify it.

Simmet said his father is firmly in the Tommies’ camp now, after wearing hats from both schools for a time. He is not the first to shift loyalties. Among the stars for the Johnnies in that inaugural game, played exactly 114 years ago on Saturday: Ignatius Aloysius O’Shaughnessy, who was later expelled, jumped ship to the Tommies and became the namesake for the stadium where the latest generation of Johnnies and Tommies will add to the story.

“People still get so excited for this game against our so-called archrival, and I think that’s always been there,’’ Fasching said. “And it probably will be there 100 years from now.’’