An own goal from Kevin Nicholson and an Allan Tait strike either side of the break were enough to continue Crawley's unbeaten home record against Scarborough.
The Reds dominated from the start and should have harvested more than just the one-goal advantage they had at half-time.
Ben Judge fired high over from 20 yards, Tait had a close-range effort saved at point blank by Leigh Walker and Simon Wormull curled a free-kick just wide.
The deadlock was finally broken after 38 minutes when Nicholson inadvertently headed Neil Jenkins' free-kick into his own goal.
The Seadogs' best chance of the first half came from a long-range effort by Neil Redfearn which Reds keeper Phil Smith did well to save.
The visitors' attacks were few and far between, however, and Crawley took just four minutes to add to their lead after the interval.
A Maurice Harkin cross eluded the sliding Dan Marney at the near post but not Tait, who tapped home his sixth of the season from two yards.
Scarborough set up a tense finish when substitute Steve Burton scrambled home two minutes from time, but their late rally faded and Crawley hung on for the win.