Middle Rasen Cricket Club gave up its top of the table position as they lost to Boston Cricket Club Sunday 2nd XI.
Heckington are now three points ahead of Middle in the Lincoln and District League Division 1.
Boston batted first and were 205 all out.
The target proved too much for the Middle batsmen to chase down, Boston restricting the home team to 175 for 7 from the allotted overs.
This Sunday Middle are at home to struggling Heighington and later in August face bottom club Hartsholme, both matches Middle will expect to win.
The outcome of the season may depend on next weekend however, when Middle travel to face title rivals Heckington.