With Lee Flynn (unavailable) and Danny Bunce (injured) missing, Dave East and Kenny Beaney came back into the starting lineup, and James Bunn replaced Jack West up front.
Junior Baker thought he had given the visitors the lead after 10 minutes, however his headed goal was ruled out for a foul inside the area.
Five minutes later, Blues took the lead as Craig Pope’s ball across the area was headed in by Jake Hall from eight yards.
The lead was doubled shortly after as Baker rifled the ball home at the second attempt after his initial effort was blocked, following a fine ball over from Luke Marshall.
With ten minutes of the half remaining Bunn held the ball up well inside the area before laying the ball off to Leon Lalite. The ex-Harlow midfielder swept the ball home from 18 yards to give Blues a commanding lead going into the break.
Grant Cooper came on for Dave East at half time with Baker moving to left back, but it was Cooper who was beaten for pace shortly after the restart as an Erith striker (number 9) tore past him on the touchline.
Joe Sweeney replaced Bunn ten minutes after the break, and had a shot which he just dragged wide. Hall intercepted a poor pass across the back, and should have scored his second of the match, but a fine tackle prevented him getting a clear shot away.
Jack West was introduced for Joao Carlos midway through the second half, and the Portuguese winger received treatment for a knock.
Baker shot well, forcing The Dockers keeper into a smart save, and it was Blues who were looking the more likely side to score.
Ryan Maxwell made it four within a minute of coming on for Beaney. Fine play down the right saw him move inside and finish low past the Erith keeper from just inside the area.
Tyrone Scarlett replaced Lalite before the home side got one goal back as the game petered out.
Blues face Harold Hill at The Academy on Tuesday, before entertaining a Dagenham & Redbridge XI at Rush Green on Thursday.
Starting line-up:- Lamar Johnson, Craig Pope, Ryan Kirby, Junior Baker, Dave East, Luke Marshall, Kenny Beaney, Leon Lalite, Jake Hall, Joao Carlos, James Bunn.
Subs:- Grant Cooper, Ryan Maxwell, Tyrone Scarlett, Joe Sweeney, Jack West