After a goalless first 45 minutes at Bolitho Park that yielded little in the way of goalmouth action, it was Iron substitute Jayden Davis’ fortuitous strike that broke the deadlock in the 65th minute.
Angelo Harrop’s side doubled their advantage soon after through Alfie Pavey, and while Rocky Neal managed to reduce the arrears with ten minutes to play, it was not enough to spare City from back-to-back defeats for the first time since November.
The result means City remain 19th in the National League South table, while Braintree have climbed two places to 11th.
City made three changes to the side that started their most recent outing, a 4-1 defeat at home to Worthing a fortnight earlier. Sam Sanders, Dan Rooney and Ryan Law returned to the starting line-up in favour of James Melhado, Adam Porter and the injured Ben Adelsbury.
There was a place among the substitutes bench for new signing Dominic Johnson-Fisher, who joined City from Isthmian League outfit Whitehawk on Friday.
Chances were few and far between in the opening 45 minutes with Shaq Coulthirst curling narrowly wide of James Hamon’s post from the edge of the box in Braintree’s best opportunity after 12 minutes.
City also struggled to test Hamon’s counterpart Jack Sims, although he did have to be alert to claim Will Dean’s powerful effort shortly before the interval, with Neal having turned Connor Riley-Lowe’s cross narrowly wide a few minutes before.
Both sides continued to cancel each other out in the second stanza, and it took a moment of fortune to break the deadlock in the 65th minute. Aaron Blair bore down on the City goal until being dispossessed by a fine Tom Harrison tackle, which cannoned off substitute Davis’ leg and flew into the corner of Hamon’s net.
That stroke of luck gave the Iron a lift and they were celebrating a second goal only six minutes later. Davis turned provider on this occasion with his left-wing cross being met by the head of Pavey, who powered the ball home from six yards out.
City chief Paul Wotton rang the changes in response and handed a debut to new signing Johnson-Fisher, and the home side got themselves back in the game in the 81st minute.
Neal was the man to give City late hope, with the forward squeezing his shot inside the far post from a tight angle to set up a grandstand finish, but Braintree managed the remainder of the game well to take the points back to Essex.