Lewes produced a fine performance on their long trek over to Guernsey on Wednesday night to ensure that Sittingbourne`s tenure at the top of the Bostik League South was a short one.
In front of a crowd of 685 at Footes Lane, it took the Rooks 15 minutes to make the breakthrough via Billy Medlock.
And just shy of the half-hour mark, Medlock doubled his and Lewes` tally.
Bouwe Bosma made it 3-0 with 6 minutes of the first half still to play, and although the Greens battled hard in the second half, they weren`t able to penetrate a solid Rooks backline as they moved three points clear at the top.
Wednesday`s other game saw Cray Wanderers make it three successive wins to move into seventh place in the table following a 3-1 win at Hayes Lane against Phoenix Sports.
Michael Power gave Cray an 11th minute lead that he added to 16 minutes later.
That was the end of the scoring until the dying embers of the game
There was a lengthy stoppage in the second half when Sports` Tony Robinson was carried off due to a serious leg injury.
And in the first minute of time added on, sub Kyron Lightfoot made it 3-0 to Cray, with Ashley Probets netting a consolation for the visitors 5 minutes into stoppage time.