Sword had a game-high 24 points and put MSU (5-1) in front for good with an old-fashioned three-point play with 1:36 left in overtime. Johnson had a career-best 20 points and also his first double-double of the season with 11 rebounds.
Sword was 8-of-12 from the floor and 8-of-10 from the free-throw line.
MSU shot 46.8 percent from the floor and was just 4 of 16 beyond the arc. Loyola shot 42.6 percent and out-rebounded the Bulldogs 35-27.
Doyle had an opportunity to win it at the buzzer for Loyola but his 3-point attempt at the buzzer was blocked by MSU's Fred Thomas.
The contest was just the third overall meeting between the two schools with the first game coming in the historic 1963 NCAA Tournament. The Ramblers won last year's meeting 59-51 in what was the 50th anniversary of that initial meeting between the two programs.
MSU and Loyola were tied at 29-29 at halftime despite the Bulldogs shooting 38 percent. Loyola shot 50 percent in the first half and led MSU in rebounding 15-13 but had eight first-half turnovers. MSU finished with just nine turnovers while Loyola had 14 for the game.
The game was tied 13 times and featured 20 lead changes.