RJ Luis Jr. made a career-high five 3-pointers and second-seeded St. John’s found its shooting stroke en route to an 83-53 victory over No. 15 seed Omaha in the first round of the NCAA Tournament on Thursday night in Providence, R.I.St. John’s (31-4) earned its first tournament win since 2000. Coach Rick Pitino and the Big East champs will face John Calipari and No. 10 seed Arkansas in the second round Saturday.Luis led all scorers with 22 points and added eight rebounds. He made 5 of 8 attempts from deep as St. John’s — a 30.4 percent 3-point shooting team entering the night — matched a season high with 14 3-pointers to counter Omaha clogging the lanes.Simeon Wilcher scored 13 points for the Red Storm. Kadary Richmond had 10 points, eight rebounds and six assists, while Zuby Ejiofor added 10 points, seven boards, four assists and three blocks.JJ White posted 15 points and five assists to lead Omaha (22-13), which was playing in its first Division I NCAA Tournament after claiming the Summit League championship.Marquel Sutton scored 11 for the Mavericks, and Isaac Ondekane pulled down 10 of his 11 rebounds in the first half.St. John’s missed its first five shots and let Omaha stake out a 7-0 lead, prompting an early timeout from Pitino. After Richmond got the Red Storm on the board, Luis scored eight St. John’s points in a row, bookended by a pair of 3-pointers.The Mavericks moved ahead 20-14 before St. John’s turned the tables. Wilcher cut the lead in half with a 3-pointer, prompting a 16-2 run that featured triples by Deivon Smith, Ruben Prey and another from Wilcher.