Sometimes, it can be simple, like the flick of a switch. A few extra passes, a few aggressive drives, play that becomes contagious, and a struggle becomes a walk in the park.

At first, St. John’s looked to be in for a dogfight against Rutgers in front of an energetic throng at the RAC. A nine-point lead was down to one. The crowd of 7,102 was worked into a frenzy. The Scarlet Knights’ size was creating problems.

But once the ball began moving, as soon as St. John’s stopped settling for contested jumpshots and started sharing, the result was a formality. A tense game began noncompetitive with Rutgers no match for the Johnnies’ small-ball, uber-talented, sharpshooting lineup.

“It was a huge step in the right direction,” junior wing Mustapha Heron said after the Red Storm crushed Rutgers, 84-65, in the Gavitt Tipoff Games, their largest margin of victory on the road against the former Big East foe. “We came into the huddle and just said ‘We’re not going to be able to do it one-on-one.’ We bought into that, and it showed. We started moving the ball, gave quicker swing [passes], [got] quicker shots and we played the way we wanted to play.”

LJ Figueroa dominated the first half, Heron and Marvin Clark II took turns owning the second stanza and Shamorie Ponds (eight points, six assists, two steals) played a strong under-control floor game as the Red Storm improved to 3-0 ahead of next week’s Legends Classic at Barclays Center.

Undersized without starting big man Sedee Keita (out 4-to-6 weeks following arthroscopic knee surgery), coach Chris Mullin was forced to go small, with the 6-foot-7 Clark his biggest player. There were stretches when the 6-6 Figueroa had that role, and the junior college All-American torched the Scarlet Knights to the tune of 23 points, 11 rebounds and four assists, continuing his impressive start.

“He’s the most energetic person on the team,” Heron said. “He can fit in anywhere. We’re just glad to have him here.”

Up 11 at halftime, the Red Storm blew the game open early in the second half, building a lead as big as 23. It became lopsided following back-to-back 3-pointers from Heron (27 points, six rebounds), each set up by Ponds. On the second one, in transition, Ponds left a between-the-legs pass for Heron, who drilled the deep jumper. It was the best the highly rated duo have looked playing together.

Heron said he believed a performance like this was coming after two inconsistent efforts to start the season. It’s a new group that is still trying to get comfortable with each other. The Johnnies faced some adversity this week with Keita’s injury, but responded just as Mullin hoped they would.

“They made a conscious effort to play with each other,” he said. “I haven’t really seen that rhythm, and I thought it really came in the second half. I just thought were really unselfish on both sides of the floor.

“For them to do this tonight, I think will give them confidence moving forward.”

Rutgers (2-1) outrebounded the Johnnies, 42-39, and 15-8 on the offensive glass, but was outscored, 15-14, in second-chance points, and couldn’t handle St. John’s at the other end of the floor. St. John’s went 16-of-32 from 3-point range, equaling a program record, and had 19 assists on 28 made field goals, evidence of the Red Storm’s selfless performance.

They took Rutgers sophomore lead guard Geo Baker (seven points) out of the game, and his teammates couldn’t pick up the slack, as the Scarlet Knights, led by Eugene Omoruyi (12 points, seven boards) and Issa Thiam (13 points), shot 34 percent from the field and missed 11 free throws.

“It shows our potential,” Figueroa said, “and what we can do.”