St. John's Red Storm guard Posh Alexander calls a play...

St. John's Red Storm guard Posh Alexander calls a play against the Butler Bulldogs during a Big East Tournament first round men's basketball game at Madison Square Garden on Wednesday. Credit: Kathleen Malone-Van Dyke

St. John’s slim hope of reaching the NCAA Tournament despite a disappointing eighth-place finish in the Big East lives on — for at least one more day.

The Red Storm opened the Big East Tournament on Wednesday afternoon by easily dispatching ninth-seeded Butler in a 76-63 first-round beatdown before a sellout crowd of 19,812 at Madison Square Garden behind strong performances by Joel Soriano and Posh Alexander.

Soriano had 19 points and 15 rebounds — his 24th double-double of the season — and Alexander continued his best stretch of this season with 13 points, including a season-high-tying three three-pointers.

St. John’s (18-14) will make its 28th quarterfinal appearance at noon on Thursday, facing top-seeded Marquette (25-6) as it looks to reach the semifinals for the 12th time and first since 2000 when it last won the championship.

The Storm were in position to reach the semifinals a year ago with a 17-point quarterfinal lead against Villanova before unraveling late and losing 66-65. Soriano said, “I think about that at times . . . but I’m in the present. We’ve got a great [matchup] tomorrow and we know what’s at stake and that we have to perform.”

The eighth-seeded Storm is seeking to salvage something from a season of underachievement, and the conference tournament title and accompanying NCAA Tournament bid is the last chance. Two years ago, Georgetown became the first No. 8 seed in Big East Tournament history to win the title.

Marquette and St. John’s played on the last day of the regular season with the Golden Eagles posting a 96-94 home victory. The Storm hopes the change to one of their home venues could make a difference.

“We have our work cut out for us, but at the same time you’re in one of the greatest events there is, the Big East Tournament,” St. John’s coach Mike Anderson said.

AJ Storr had 15 points, David Jones 12 points and Dylan Addae-Wusu 10 points and 10 rebounds for St. John’s. Simas Lukosius had 23 points and Jalen Thomas had 20 points for Butler (14-18).

Alexander has at times looked like a shadow of the player he was in his first two seasons in Queens. But his inconsistent play has ebbed into a strong finish, with him averaging 15.0 points his past five games.

“I was playing bad — I wasn’t playing to my best ability and I was getting in my head,” Alexander said. “I talked to my family and they just told me ‘Remember where you came from and how hard you worked for this opportunity.’ I just thought about it, started getting to the gym a lot more, shooting the ball and getting my confidence.

“It’s more just me having confidence in my game, and the last couple games showed it.”

Soriano had 11 of his points and Alexander 10 as St. John’s built a 36-25 lead en route to a 44-29 halftime lead. The Storm was meeting little resistance, making 54.3% of its shots and outrebounding the Bulldogs 24-11..

“As a coach you always wonder how your team’s going to come out,” Anderson said. “Our guys I thought came out with good energy and made some shots early, established inside, did a good job getting to the glass.”

Newsday LogoYour Island. Your Community. Your News.Digital AccessOnly 25¢for 5 months