Wyberton were beaten 1-0 at Sleaford Town in the Lincolnshire League on Saturday.
Following four straight victories - including wins against highflying Skegness Town, Hykeham and Skegness United - Gary Frost’s in-form side finally came undone by a solitary goal.
Wyberton remain second in the standings, a point behind leaders Skegness Town and two points clear of third-placed Horncastle Town, although teams around them all have games in hand.
On Saturday, Wyberton are looking to bounce back as they travel to face ninth-placed Nettleham.
Nettleham have won four and lost six of their 11 matches in the league to date.