Wagner never led at any point. The Colonials (17-8, 9-3 Northeast Conference) shot 58.3 percent (14 of 24) while building a 42-27 halftime lead, scored five points in the first 9 seconds after halftime and still led 64-53 with 5:45 remaining.
Kenneth Ortiz and Latif Rivers, who each scored 22 points, led the Seahawks (13-10, 7-5). Rivers' layup with 13 seconds left brought them within 72-71. After Jones hit 1 of 2 free throws, Ortiz's layup with 6 seconds left forced overtime.
Two free throws by Jones and a layup by Johnson gave Robert Morris a 77-73 lead, and the Colonials hit all eight of their overtime free throws.
Robert Morris has won nine of its last 10 and clinched its eighth straight winning season.
Mike Krzyzewski says he has good reason to be excited for next season thanks to a combination of Duke's incoming freshmen and a core of experienced upperclassmen.
Georgia guard Juwan Parker has been awarded a medical redshirt, leaving him with two years of eligibility, after missing the 2015-16 season with a partially torn Achilles tendon.
Forward Trevon Bluiett has withdrawn from consideration from the NBA draft and will return to Xavier for his junior season.