Deeping Rangers must wait for a chance to bounce back from a second successive home defeat.
They were already without a fixture on Saturday and next week’s trip to AFC Rushden & Diamonds is off because the Northamptonshire club are in the FA Cup first qualifying round.
That also means Rangers midfielder Scott Ginty has not completed a three-match ban.
Peterborough Northern Star made it five unbeaten visits to Outgang Road with Tuesday’s last-gasp success.
Phil Stebbing’s deflected shot struck the bar but he put Star in front after 53 minutes, latching onto Simon Ashton’s misplaced header to run clear and slot past Danny Bircham.
Deeping levelled after 84 minutes with Ben Lewis’ shot hitting the post and going in off keeper Dan George.
But three minutes into added time Luke Avis fired home the winner.
Deeping: Bircham, Braithwaite, Smith, Ashton, Holland, Burton-Jones, Flack, Bogusz (Lewis), Oliver (Graham), Heron, Porter (Lee).