Roberts was 14 of 18 from the floor, including three 3-pointers, to become the first Spartan to reach 30 points since November 2012.
Rogers had 23 points on 10-of-11 shooting in the first half that ended with the Spartans leading 43-42. San Jose State took the lead for good with a 10-1 run for an eight-point lead with 7:11 left. The Seawolves were within four with 15 seconds before Williams made two free throws.
Sekou Wiggs led the Division II Seawolves (6-4) with 30 points with Spencer Svejcar adding 19 and Diante Mitchell 13.