Bridon Ropes had beaten the Rustics at Jockey Farm earlier in the season and looked a better side than their second-from-bottom position would suggest.
The first half was a tight affair with chances at a premium for both sides, but three minutes before the interval Rusthall broke the deadlock with a first goal of the season for Lorenzo Cuozzo.
The visitors’ delight was short-lived, however, with Gibson Dobson equalising for Bridon Ropes two minutes into the second half.
But four minutes later Rusthall regained the lead when Tommy Lawrence’s corner sailed straight into the net.
From this point the game became scrappy with neither side seemingly able to hold onto the ball long enough to create danger.
Then in the 66th minute Jack Kirby stunned the Rustics with an equaliser. Bridon proceeded to defend stoutly until the 87th minute when Powell-Downey took his goal well.
It is getting tight at the top of the table with just four points separating the top five sides and four to go up end of the season.
Rusthall are now at home to Sutton Athletic on Saturday (February 1, kick-off 3pm).