Twenty years after beating Georgetown in arguably the greatest upset in the NCAA Tournament championship history, Villanova (21-6) is back among the nation’s elite teams. The Wildcats begin play today in the Big East Tournament with a quarterfinal-round game against Pittsburgh (20-7).

Villanova’s 66-64 championship in 1985 was marred by point guard Gary McLain’s admission that he was high on cocaine the entire season. In an upcoming HBO documentary, “Perfect Upset,” which airs March 28, McLain insists he was clean the night he scored eight points, handed out two assists and withstood the vaunted Georgetown pressure.

“For the record, I was not under the influence or any mood- or mind-altering substances in the championship game,” McLain tells HBO. “Bottom line. Won it. Can’t take it from me. MVP of the game. I don’t believe what I’ve been through can tarnish the magnitude of what we accomplished.”

Villanova hasn’t been to the NCAA Tournament since 1999. Three years ago, it hauled in one of the nation’s top recruiting classes and one national publication picked ‘Nova its preseason No. 1. Injuries and a telephone-credit-card scandal prevented ‘Nova from reaching its potential.

“I feel so good for these kids, who are really good kids and have been through a lot,” said Villanova coach Jay Wright. “The first obstacle they’ve confronted is the high expectations. Some people got down on them but they never did.”

Sounds like the ’85 team.