The win means Sleaford are fifth in the standings going into the midweek fixtures, nine points behind leaders Loughborough Students but with three games in hand.
All the goals came in the second-half, but there was initially drama in the first period as Melton player-manager Tom Manship was sent off on 18 minutes for a challenge on Charlie Ward, home defender Henry Eze also sin-binned following a melee in the aftermath leaving the hosts temporarily down to nine men.
The Greens took full advantage after the break, Rushen heading them in front on 48 minutes from Jacob Fenton’s cross.
The same duo combined again eight minutes later, Fenton’s cross this time bundled in by Rushen to double the lead.
Rushen then completed his hat-trick in the space of 15 minutes, netting from a rebound after Akeel Francis’s shot had been parried by the keeper.
Melton’s Sam Muggleton then reduced the arrears from close range on 68 minutes, and despite both sides missing opportunities to add to their totals it was Sleaford who went on to claim all three points.
Hat-trick hero Rushen said afterwards: “I’m really happy. It’s my first hat-trick for Sleaford but it was all about the three points today as we’ve got games in hand and were up against second-placed Melton who are a really good side.
"Obviously things changed after the red card and it was attack after attack from us but at half-time we said we needed not to rush or try and win it in the first ten minutes of the second-half, we had a change in formation and it worked.”
Sleaford are back in action on Wednesday night (26th) when ninth-placed Kimberley Miners Welfare are the visitors, before League Cup action takes over on Saturday when the Greens head west to face Coventry Sphinx.
That’s then followed by another home game on Tuesday as Wisbech Town visit Eslaforde Park.