David Cobb and Olly Medwynter scored the goals as Peterborough Sports made it 16 wins from 16 games in United Counties Division One with a 2-0 success over Potton on Tuesday.
Sports are without a game this Saturday giving their fellow promotion hopefuls the chance to eat into their 11-point lead at the top.
The city side are next in action at home to top Thurlow Nunn Premier Division side Godmanchester Rovers in a tasty-looking quarter-final tie in the Hinchingbrooke Cup next Tuesday (December 15).
Bourne scored twice in the last couple of minutes through Tyler Sculthorpe and Dan Smith to draw 2-2 with Thrapston in Division One last weekend.
Blackstones suffered two three-goal defeats in four days at the hands of Lutterworth and Thrapston respectively.