Jersey director of rugby Ben Harvey has urged the island's population to get behind his side for Saturday's top-of-the-table clash with Rosslyn Park.
Jersey are a point behind their opponents who lead National One and are the first visitors to St Peter in 2012.
"For the Blackheath game the boys were surprised that we had almost 2,000 people watching," Harvey said.
"Coming out of that changing room and hearing that roar makes a huge difference," he told BBC South West.
The island side have averaged crowds of around 1,500-2,000 this season but have had as many as 5,000 through the doors for big matches such as last season's National Two play-off with Loughborough Students.
"If we could get 4,000 there this weekend that would be a 16th man there which would obviously be hugely important for the team.
"If people are wondering what to do on Saturday afternoon, get yourself down to St Peter's," he added.
While Harvey would not be drawn on whether the Rosslyn Park game was the most important of the season, he did reiterate that his side had to keep up their good form.
Jersey have won their last 12 matches, a run which stretches back to the beginning of October.
"The nature of this league is such that in effect we could win every game but still not come top because of the bonus points," he said.