At the Broadfield Stadium, Josh Simpson and Hope Akpan both saw red for Crawley after picking up two yellow cards, before teenager Ashley Harris put the visitors in front in the 71st minute. Late goals from Luke Rodgers and Izale McLeod sealed the win.
Stevenage registered their second victory of the campaign with victory against Coventry at the Ricoh Arena.
The home side took an 11th-minute lead through David McGoldrick but 10 minutes later Robin Shroot equalised, before Marcus Haber won the game for the away side in the 71st minute.
