As other results went for them, they couldn't have asked for a better script which brought a penalty inside five minutes against a struggling side low on self-belief.
With a neat little shuffle, Phil Jevons sent Brentford keeper Nathan Abbey the wrong way and the springboard was there for Gary Johnson's side.
It didn't quite work out that way and, the longer the killer goal failed to materialise, the more Brentford began to sense they might get something out of the game.
Duffed up the week before by league leaders Scunthorpe, they felt hard done by after the award of the spot-kick for handball against Kevin O'Connor.
A week ago he blazed a penalty out of the ground and now he gave away one by finding himself in the direct firing line of a thumping drive from Enoch Showunmi. It was the sort of decision that goes against you when you are at the wrong end of the table.
With two shots from Showunmi and a header from Jamie McCombe scooped from under the bar, City shaped to steamroll their way to victory, but the chances became misses because the finishing wasn't good enough.
Early in the second half Showunmi towered over defenders as he stretched for a Lee Johnson corner but didn't quite get enough head on the ball and the glance went wide.
Then, from another swinging corner, McCombe rattled the bottom of a post - but the two most important misses came from Jevons.
The penalty had been his 16th goal this season, but he should have added others as he was put in by first Brian Wilson and then Kevin Betsy.
They were the providers in City's new-wing back system but neither made the most of their speed.
Brentford's best chance came from the unlucky O'Connor. Moving up for a free-kick after Scott Taylor had been fouled by Betsy, he got in a great shot which was tipped over the bar late on by Adriano Basso.