The Bees were heading for a 1-0 defeat at the Fraser Eagle Stadium before Ipswich Town loan striker Jordan Rhodes pounced to net a dramatic last-minute equaliser.
And with a battling draw Andy Scott's side leapfrogged Wycombe Wanderers to make sure of their place at the summit.
James Ryan's third goal in six games looked to have condemned the Bees to a sixth league defeat and a second loss in their last three matches.
But Rhodes' stoppage-time volley snatched a point for the visitors as they stung the hosts in cruel fashion.
Midfielder Ryan has now scored seven goals this season - and tonight's goal couldn't have come at a better time for John Coleman's side who were sitting 16 places below their opponents before kick-off.
The visitors could have taken the lead in only the first minute, but goalscorer Rhodes saw his header tipped over the crossbar by Stanley keeper Kenny Arthur.
Stanley rallied and Phil Edwards headed over at the other end as the hosts nearly snatched the opener.
Sam Wood then had two good chances for the visitors. First seeing a shot blocked, before firing wide from a good position.
Paul Mullin, back for Stanley after an ankle operation, then forced Brentford keeper Ben Hamer to make a smart stop.
Leam Richardson had a shot tipped around the post by Hamer, while at the other end Wood shot wide.
Alan Bennett headed over for Brentford, before Mullin forced Hamer to make a good block.
The opening goal came three minutes after the break thanks to a clinical strike from Ryan, but Brentford battled right until the end.
Ryan could have had a second but for a good save from Hamer, before Charlie MacDonald shot over and Nathan Elder had a shot saved.
But it was Rhodes who helped the Bees go top of the table as they continue their quest to get into League One.