Ealing Trailfinders suffered a surprise 27-8 away defeat to Barking after a sensational second-half performance by the east Londoners.
Despite being on the back foot in the first half, Barking made the most of their dominance in the second period to stun their high-flying visitors.
It was only their second defeat of the season but leaves them even further behind divisional favourites London Scottish.
Barking fly-half Craig Ratford kicked a penalty to put Barking into an early lead before Ealing set up permanent camp in the home team's half for the duration of the first 40 minutes.
But a resolute Barking defence refused to buckle and only a sublime offload from the tackle by Pete Hodgkinson allowed Ealing's David Howells to cross in the left corner to give the visitors a 5-3 lead after 15 minutes.
Time and again, Ealing hammered away at the Barking line with little success, conceding turnovers and penalties in equal measure to lose the initiative.
On only their second foray into Ealing territory, Barking won a penalty that Ratford kicked from long range to again put the home side ahead.
As the first half ticked away, Ealing resumed their siege of the Barking goal line, but could only manage a Ben Ward penalty on the stroke of half-time for their efforts.
The second half was all Barking. A wayward pass from Ealing scrum-half Dan
Smaje gifted Barking a fivemetre scrum and the home side worked through the phases to create room for prop Sean Mullins to break through and score his side's first try of the game. Ratford kicked the simple conversion.
Like their hosts in the first half, Ealing were unable to break out of their own half and a constant flow of errors and penalties did nothing to help their cause and Ratford gladly accepted the invitation to kick two more three-pointers to extend Barking's advantage to 19-8.
With their tails up, the home side began to mix up their game to great effect, giving Ealing little time or space to create any serious threat and sealed the game with a fantastic try with 10 minutes to play.
Barking centre Alec Jenkins collected an Ealing clearance kick and a kind bounce allowed him to gather his own chip over the advancing defence and set up a two-onone.
He timed his pass to perfection to give prop Gareth Hoadley a clear run for the line down the right touchline.
Ratford missed the conversion but added a fifth penalty late on to take his personal tally to 17 points for the afternoon.
This Saturday (2pm) Ealing host Havant at Vallis Way. The Hampshire outfit, one place off the bottom of the table, registered their own shock last weekend, with a 32-10 win over Dings Crusaders.