Stevenage boosted their play-off bid and left Scarborough deeper in trouble.
Adam Miller gave Borough the ideal start when he unleashed a wicked low drive from 25 yards which whistled past Scarborough goalkeeper Ian Dunbavin.
George Boyd effectively ended the game as a contest when he drilled home his 12th goal of the season.
Scarborough improved and Neil Redfearn, Jason Blunt and Chris Hughes all went close but Borough held on for a 14th home win of the season.
Stevenage: Julian, Goodliffe, Oliver, Henry, Maamria, Miller, Boyd, Bulman (Gregory 70), Berquez, Nurse (Louis 65), Stamp (Weatherstone 83).
Subs Not Used: Gore, Warner.
Goals: Miller 10, Boyd 21.
Scarborough: Dunbavin, Steve Baker, Nicholson, Weaver, Atkinson, Fowler, Redfearn, Blunt (Ingram 65), Hughes (McNiven 83), Coulson, Hackworth.
Subs Not Used: Walker, McClare, Beadle.
Booked: Steve Baker, Coulson.
Ref: D McDermid (Hampshire).