The Ironsides take on Longlevens in Earlsfield on Saturday (kick-off 2.30pm) in the regional final of the RFU Junior Vase, with a place in the national final at the home of rugby up for grabs.
Since their Vase campaign started in October, crowd numbers have grown with each passing round, until almost 200 fans saw the Ironsides beat Seaford last month to win the London final, pictured below.
Now, with Twickenham one win away, O’Keeffe wants fans to play their part.
He said: “This is not just a game for the rugby club, this is a game the whole community can get behind.
“Some people may not even know we exist or have an interest in rugby, but getting to Twickenham would be huge for the area.
“This will be grass roots, amateur rugby at its very best, and it would be great to have a good crowd to cheer us on, and who knows, we might inspire the next generation of rugby stars.”
He added: “There is not one person connected with the club who is not aware of the incentive of Twickenham, there is massive excitement.”
While Ironsides signed off an inconsistent Surrey One league campaign last weekend with a confidence- boosting 33-17 win over Old Tonbridgians to finish fourth, Longlevens’ final game of their season was postponed.
However, prior to that, the Gloucester One side had gone 10 games unbeaten – something that does not concern Irishman O’Keeffe.
“They are very quick and skilful on the wing, which is the opposite to our style,” he said.
“But I am quietly confident, and we’ll know all we need in the first five or 10 minutes of the match.”