Although the Wands have only won two League games at home this season, this was their sixth away win, and it came in good style against opponents who are pushing for a play-off promotion place.
Cray took the lead on 13 minutes when Leigh Bremner netted from the penalty-spot after handball by a home defender.
Cray defended well against strong pressure from the Blues before Reynolds equalised on 35 minutes.
Bremner restored Cray's lead with a bullet-header on 50 minutes, and then the Wands romped into a 4-1 lead as Paul Booth and Chris Saunders added goals in the 55th and 75th minutes.
Knight netted a consolation goal for the home side near the end.
Cray: Walker, Pooley, Clark, Day, Willy, Stavrinou, Long, Saunders, Bremner, Booth, Fray.
This win has put further distance between seventeenth-placed Cray and the five teams below them. The bottom two will be relegated.
Cray are away to AFC Wimbledon in the London Senior Cup quarter-final on Wednesday (7.30pm).
In their next Ryman Premier League match Cray are at home to Lewes on Saturday (3pm).