The visitors had to come from behind after Simon Wormull gave the Reds a 12th minute lead with a curling free-kick from just outside the area.
Steve Burton should have doubled the advantage for the hosts two minutes later when he fired wide after beating the offside trap to go clear on goal.
Jamie Cade then missed another golden chance for Crawley when he sidefooted tamely straight into the arms of keeper Nicky Eyre from six yards despite having the whole goal to aim at.
Grays equalised against the run of play two minutes before half-time following a mistake by home keeper Phil Smith. He fumbled a cross by Glenn Poole to the feet of Gary Hooper, who squared for Jamie Slabber to slot into an empty net.
Cade almost hit back on 73 minutes when he had a shot blocked from close range by defender Jamie Stuart.
Crawley were paid to pay two minutes later when Dennis Oli put Grays ahead with a cool finish under Smith after latching on to a neat through ball by Slabber.
Oli sealed the points for the Essex side in the last minute with a shot from just inside the area following a long clearance by Stuart Thurgood.
Steve Burton should have doubled the advantage for the hosts two minutes later when he fired wide after beating the offside trap to go clear on goal.
Jamie Cade then missed another golden chance for Crawley when he sidefooted tamely straight into the arms of keeper Nicky Eyre from six yards despite having the whole goal to aim at.
Grays equalised against the run of play two minutes before half-time following a mistake by home keeper Phil Smith. He fumbled a cross by Glenn Poole to the feet of Gary Hooper, who squared for Jamie Slabber to slot into an empty net.
Cade almost hit back on 73 minutes when he had a shot blocked from close range by defender Jamie Stuart.
Crawley were paid to pay two minutes later when Dennis Oli put Grays ahead with a cool finish under Smith after latching on to a neat through ball by Slabber.
Oli sealed the points for the Essex side in the last minute with a shot from just inside the area following a long clearance by Stuart Thurgood.