For 45 minutes Oakham United had the measure of Peterborough Sports Parkway, going in 1-1 at half-time on Saturday.
But two strikes early in the second half rocked the Rutlanders and the league leaders pulled away to win 6-1 and strengthen their title prospects in the process.
Robbie Dance had pulled Oakham level with a 20 yard strike after Kev Brader’s opener midway through the first half.
But, after a resilient first half, Oakham were undone just a minute into the second half and by the 55th minute they were 3-1 down.
Three goals in the final 17 minutes added gloss to the scoreline for the City side.
Oakham’s joint manager Pat Johnson said: “For 45 minutes we were very good, drawing with the league leaders but in the second half we fell away.
“Perhaps fitness told a little but we also gave the ball away too easily.
“They made it three quickly and heads dropped. But I was pleased with the first half.”
Oakham had opted for a 3-5-2 formation for the first time.
“Most teams are playing that way now and we did not have the players to play four at the back,” said Johnson, whose side was depleted by absences including Shane Hicks and Eddie McDonald, who are not expected to play again this season.
Oakham are at home to bottom side King’s Cliffe United on Saturday. Kick off at Oakham’s Catmose College is at 2pm.
Oakham: Andy Collin, Jamie Saddington, Jamie Forbes, Tom Bain, Steve Smith (Ben Jones), Craig Welbourn, Robbie Dance, Robbie Pearce, Stu Lambie, Nathan Arkle, Alex Brockbank.