The win sees the Reds leapfrog the Bluebirds into 18th in the table. John Yems' side have now taken 20 points from 16 games.
Barrow had an early effort hacked off the visiting goal-line before Ludwig Francillette and Jake Hessenthaler both had goal-bound attempts well blocked.
Crawley's first clear cut opportunity came on 22 minutes. Kwesi Appiah skewed his half-volley just wide of the target.
Tilley then fired wide on the half-hour mark before Remeao Hutton, who was left wide open and had plenty time to shoot, smashed his shot over the bar as the half drew to a close.
The Reds opened the scoring on 57 minutes. A good interception from Appiah saw the Ghanaian release Tilley who fired past Barrow keeper Paul Farman and into the bottom-right corner.
Crawley stopper Glenn Morris, who was large untroubled by the Bluebirds, was called on to make an unbelievable stop at the death.
Will Ferry's loose header fell to Barrow's Joe Grayson in the area but Morris made himself large and used his body to block the defender's close-range strike.
Crawley Town: Morris, Davies, Francillette, Craig, Francomb, Frost (Ferry 69), Hessenthaler, Powell, Tilley (Ashford 85), Nadesan (Nichols 69), Appiah. Unused: Nna Noukeu, Battle, Kowalczyk, Bansal-McNulty.
Referee: Samuel Barrott