The Stags failed to hold onto a draw as James Tilley’s added time volley gave the Red Devils the three points and saw them move into the top half of the League Two table.
Mansfield Town had the first chance of the half through Jamie Reid. The forward tried an overhead kick with the effort pushed away from danger by Glenn Morris.
Tom Nichols headed the ball towards the Stags goal which saw Marek Stech claim the effort with relative ease as both sides searched for a goal.
Reid was at it again as he looked to head the ball into the back of the net but skewed his effort wide of the goal from a pinpoint Stephen Quinn delivery.
Nichols look to curl an effort beyond Stech but the experienced goalkeeper made a step to the side and once more claimed the ball with relative ease.
Two shots from Reid and Jordan Bowery went over the bar and wide of the target as the referee blew his whistle to indicate the end of the first-half.
Half-Time: Crawley Town 0-0 Mansfield Town
Stech was able to make a good save as the Mansfield goalkeeper got down low to deny Nichols and keep the Crawley striker out.
Archie Daniel Davies’ delivery was met by Ashley Nadasan as the forward head over the bar as the Red Devils continued to find a way through.
Jordan Maguire-Drew had a go directly from the free-kick but it was another effort that sailed over the bar and failed to hit the target.
Substitute Josh Tilley secured the three points for the host after a long throw was hoisted in and the forward struck the ball on the half volley as it made its way past all the defenders and beat Stech at his near post.
Full-Time: Crawley Town 1-0 Mansfield Town
Man of the Match: Glenn Morris
The Crawley shot stopper had a relatively calm and laid back afternoon but when he was needed the goalkeeper made vital stops to keep the Mansfield attackers away.
A clean sheet and three points is what every goalkeeper wishes for and it was Morris who was able to fulfil that goal as Stech failed to keep a clean sheet and his side missed out on a valuable point away from home.