Ollerton Town failed to take advantage of an early goal and Retford being reduced to 10 men for half-an-hour as they were held 1-1 by the bottom club.
Gav King scored his 18th goal of the season to put Ollerton ahead inside the opening five minutes.
Retford’s Callum Littlejohn levelled 10 minutes into the second half, but was dismissed five minutes later for his part in a melee.
Ollerton scored after only three minutes when King converted a low cross from the right by full back Tom Moody.
The home side remained on top for the rest of the half but could not add to their lead.
Striker Kyle Ludlow was unable to take advantage of a one-on-one situation while Lewis Bingham fired straight at the keeper and King was also denied by Gamble.
Retford, bolstered by several recent new signings, started the second period well. Reece Treasure’s header struck the woodwork before Littlejohn evaded a couple of strong challenges and fired past McCormack.
Five minutes later, however, the goalscorer was dismissed.
Ollerton could not make their advantage count and Retford might have snatched an unlikely win in stoppage time when substitute Callum Chambers shot wide.