Sophomore guard Jeff Dowtin Jr. had 16 points, 10 assists and six rebounds for Rhode Island. (Alex Brandon/Associated Press)

An instant after his three-pointer gave Rhode Island a five-point lead over Saint Joseph’s with 19 seconds left Saturday, Jeff Dowtin Jr. turned to his left and caught Coach Dan Hurley’s eye.

“I gave him a little look,” the sophomore guard from Upper Marlboro, Md., said after the riveting 90-87 victory in an Atlantic 10 tournament semifinal at Capital One Arena. “He gave me a look back like, ‘Yeah, big shot. It’s go time.’ ”

A few rows behind the Rams’ bench, Dowtin’s friends and relatives numbering about 20 rejoiced. A moment later, before he dashed to a joyous locker room, Dowtin stepped into Section 121 to join his supporters for congratulatory hugs. Parents and grandparents, aunts and uncles.

The graduate of St. John’s College High School in the District, the only non-senior starter on the 25th-ranked team in the nation, was exceptional in helping top-seeded Rhode Island (25-6) continue its pursuit of consecutive conference tournament championships.

Third-seeded Davidson, an 82-70 winner over second seed St. Bonaventure, awaits in Sunday’s 1 p.m. final.

The Post's Neil Greenberg analyzed NCAA statistics from the past seven March Madness tournaments to give you pointers on how to make a winning bracket. (Monica Akhtar,John Parks,Sarah Hashemi/The Washington Post)

The Rams will attempt to become just the third top seed since 2006 to win the title and the first repeat champion since Temple from 2008-10.

Dowtin helped get them within one step by scoring 16 points on 6-of-8 shooting, including 3 of 4 three-pointers, recording 10 assists (eight in the second half) without a turnover and adding six rebounds.

A day earlier, he made 7 of 10 shots and scored 18 points in a quarterfinal triumph over eighth-seeded Virginia Commonwealth.

During the regular season, he averaged 9.2 points and 5.5 assists, second best in the conference. His assist-to-turnover ratio of 4.6 topped the league and, entering the weekend, was third best in the country.

Hurley said “it’s been a game-changer” since Dowtin became a starter in the middle of his freshman season. “He’s a winner, high IQ. Makes big shots. Keeps everyone around him calm. Great leader. And he’s becoming a better shooter. That three he hit, that’s how you win. That’s how you get to championship games.”

A minute before the critical three-pointer, Dowtin hit a 15-footer for a five-point edge. Two free throws by Saint Joseph’s created the same situation — and another opportunity for Dowtin.

Hurley waved his top scoring threat, Jared Terrell, to back farther off on the right wing, creating isolation for Dowtin to step back and hit the jumper from the left of the key.

“I was able to create separation,” he said. “I’ve worked on that move since high school. Once you see the ball come off your hands like that, you just know it’s going in.”

His three-pointer was the last of the Rams’ season-high 14 (on 30 attempts). Fatts Russell and E.C. Matthews (14 points apiece) as well as Terrell (13) also made three each.

Andre Berry, a 6-foot-8, 275-pound forward, had 18 points and nine rebounds as the Rams avenged a 30-point home loss to the fourth-seeded Hawks (16-16) less than two weeks ago.

Shavar Newkirk led Saint Joseph’s with 18 points, eight rebounds and six assists. The Hawks led by 11 early in the second half and shot 56 percent, including 9 of 18 three-pointers, but conceded 19 offensive rebounds and 21 second-chance points.

They had a chance to tie, but needing to go the length of the court with 2.2 seconds left, Taylor Funk traveled after catching the inbounds pass near midcourt.

In the other game, senior Peyton Aldridge (24 points) made 6 of 7 three-pointers and freshman Kellan Grady (23) converted four as Davidson (20-11) advanced to the final for the first time since joining the Atlantic 10 in 2014-15.

Its only defeat in the past month was a 117-113, three-overtime thriller at St. Bonaventure.

“We didn’t hang our heads after the game and still believed we were capable of beating them,” Grady said.

The Wildcats shot 56 percent and hit 16 of 29 three-pointers in ending St. Bonaventure’s winning streak at 13. “Seemed like they only missed about three of them,” Bonnies Coach Mark Schmidt said.

The three-point total was the second most in A-10 tournament history. Ten of Davidson’s 13 first-half baskets were from distance.

Jaylen Adams had 20 points and eight assists for the Bonnies (25-7), who, at No. 21 in the Rating Percentage Index entering Saturday’s games, are well-positioned to gain an NCAA tournament at-large berth.

“I think we’re going to have a good day tomorrow,” Schmidt said.