Eitan Chemerinski had 15 points for the Big Red (5-8), who had been 0-5 on the road this season.
St. Francis (Pa.) has lost 13 games in a row dating back to last season.
The Red Flash closed the gap to three points at 58-55 on Greg Brown's free throws with 8:33 to go in the game, but baskets by Peck and Galal Cancer made it 62-55 at 7:38.
The Big Red opened an 11-point advantage at 74-63 at the 2:50 mark on Gray's 3-pointer and cruised home to the victory.
Gonzaga has signed California transfer Jordan Mathews to a financial aid agreement for the 2016-17 season.
Coach Gilmore on CWS win: 'It's indescribable' Coastal Carolina head coach Gary Gilmore reflects on his 21 years as head coach and is proud of how far the program has come.
Two late June events provided a great start on the 2020 class and a look at some new 2019 talent.