Full-time: Braintree 1, Robins 0
Cheltenham Town's lead at the top of the Vanarama National League was cut to just one point after this disappointing defeat by Braintree Town.
Michael Cheek's second half header handed the play-off hopefuls a hard-earned victory, and consigned the Robins to only their fourth loss this term at the chilly Avanti Stadium.
The Essex side are this season's surprise package, but their approach isn't one for the purists.
Their defence is the second meanest in the division, behind the Robins, and they frustrated the highest scorers all afternoon.
But the reality is that on this occasion Cheltenham couldn't create enough to test The Iron's goalkeeper Tom King.
The first half was a niggly affair, with four Cheltenham players picking up yellow cards in a real scrap.
Cheltenham looked much better after the interval, but the goal came against the run of play and in the end sheer determination got Braintree over the line.
Gary Johnson made just one change at left back, bringing back George McLennan in place of Jordan Cranston.
The Iron, in their garish orange strip, started the game the brighter of the two sides and enjoyed the better of the scruffy opening exchanges, without really testing Jon Flatt in goal.
Danny Wright, Dan Holman, Jack Barthram and Jack Munns all fell foul of the referee as the Robins struggled to get a foothold in the contest, with Holman and Barthram going into the book for late fouls.
The first real chance of the game fell to Michael Cheek midway through the first half, who called Flatt into a diving save to his right from six yards.
Moments before Kyle Storer had headed a Jack Munns corner straight at Tom King, the Braintree number one, but it was comfortably held.
By this point Gary Johnson' side were getting increasingly frustrated with the home side's agricultural approach to the match.
Munns was the third Cheltenham player to be cautioned, for a foul, quickly followed by Storer for dissent.
But they settled at this point, concentrated on their football and began to test Braintree as the half drew to a close.
There was a chance for Wright after some good work by Holman to make the chance, while James Rowe sent one well wide from distance.
There were two changes at the break, with James Rowe and Jack Munns making way as Johnson switched to 4-3—3 after the break.
On came Harry Pell and Amari Morgan-Smith and with news of a Tranmere Rovers equaliser at Prenton Park to peg back title rivals Forest Green Rovers, and a burst of noise from the large travelling support, Cheltenham began to test Braintree.
Asa Hall smacked the upright from 20 yards, and it rolled across the gaping goal. Danny Wright stabbed home, with the help of a defender, but it was ruled out for office.
At the other end the Robins were indebted to a smart goal line clearance by Dan Parslow to deny Dan Sparkes from the edge of the box.
Then Tom King pulled off a fine save to prevent Morgan-Smith, who brought down Harry Pell's diagonal ball on the penalty spot but could find a route to goal.
But Braintree got the winning goal with 27 minutes to play after Dan Parlsow misjudged a cross from the left to allow Cheek to get to it and arch a header over Flatt.
It came against the run of play, as Cheltenham began to look more dangerous, and it was harsh on Parslow who was otherwise flawless.
Booking number five followed, waved at Cameron Burgess for pulling down substitute Sean Marks.
The ball was floated into the box, but Flatt was equal to Sim Akinola's glancing header.
In a flash, Cheltenham broke down the other end but Holman looped an effort over King, and well over the bar.
Next Kyle Storer delivered a magnificent ball from the right, but Wright's deft header flew inches wide of the left upright.
Harry Pell, who was pressed into attack in the closing stages, had the chance to smash an 18-yard free-kick with four minutes to go but the defensive wall did its job.
Then Holman didn't catch Wright's ball cleanly enough to test King from 10 yards out, and it pretty much summed up his side's afternoon.
CHELTENHAM TOWN (4-4-2): Flatt; Brathram, Parslow, Burgess, McLennan; Munns, Hall, Storer, Rowe; Holman, Wright. Subs not used: Lovett (Gk), Waters, Morgan-Smith, Cranston, Pell.
BRAINTREE TOWN (4-4-2): King; Long, Phillips, Fry, Habergham; Sparkes (Brundle 76), Davis, Isaac, Akinola; Cheek (Marks 68, Edgar 86), Davis. Subs not used: Miles, Edgar, Powell.
REFEREE: C Hatzidakis
ATTENDANCE: 1,138 (216 away)