Four more goals seal victory.
Despite the game against Tottenham twenty-four hours earlier, the U's took a strong team to the Amlin Stadium and were rewarded with three quick fire goals in the first half hour of the game that gave them a position they didn't give up.
Andy Bond broke the deadlock for Joe Dunne's men, hooking over his shoulder from close range after the goalkeeper was unable to clear.
And, not long afterwards, Marcus Bean doubled the advantage as his long range shot could only be parried into the goal by the home shot stopper.
The U's had to wait until the half hour mark as Freddie Ladapo got to the byline and his low ball across the area was turned home into his own net by a Braintree defender.
The second half saw Braintree change a number of their players and their second half side put the U's under more pressure.
Town got a goal back as a ball into the box by Kenny Davis was nodded home by Sean Marks, who continues to grabs goals on a regular basis for Braintree.
However, right at the death, the U's got a fourth to extend their advantage as Ryan Melaugh, only just introduced as substitute, made no mistake as he got into the box to slide home a finish for Joe Dunne's men.
The pre-season fixtures now move into their final week with matches against Ipswich Town, Histon, Needham Market and Maldon & Tiptree.