The NCAA Tournament drought for St. John’s ended Sunday as the program earned a No. 9 seed in the South Region and a matchup with San Diego State.

It was part of a bittersweet day for the Red Storm, who earlier Sunday suspended big man Chris Obekpa two weeks for what sources told The Post was a failed marijuana test, which means he won’t return unless they reach the Final Four, a long-shot task made immeasurably harder by the loss of Obekpa.

The committee did not let that news affect the St. John’s seeding too much. The team was projected to fall between a No. 8 and No. 10 seed.

If St. John’s is able to dispatch the Aztecs, a defensive force from the Mountain West Conference coached by Steve Fisher, it likely would face Duke — the South Region’s 1 seed — who will take on the winner of a first-four game between Robert Morris and North Florida. St. John’s lost to Duke 77-68 at Madison Square Garden in late January.

St. John’s was last in the NCAA Tournament in 2011, Steve Lavin’s first year as coach in Queens, when his squad lost to Gonzaga in the opening round.