Third-placed Bourne closed the gap at the top of the table by beating Bracebridge Heath at Abbey Lawn on Saturday.
The league leaders struggled to find their form with the bat as Bourne only conceded five extras.
Colin Cheer, Jack Berry and Tom Dixon each claimed two wickets as Bracebridge Heath were restricted to 185-9 off 50 overs.
Bourne were helped in their reply with 42 extras – but they looked in trouble at 88-6 following three wickets each for Alex Willerton and Matthew Carter.
A partnership of 75 from Dixon (45) and Rob Dunn (35no) helped Bourne to their target in the 41st over. Dixon hit five fours and a six in his 44-ball knock.
Meanwhile, a five-wicket haul by Jonathan Miles set up Spalding’s victory away to Grimsby, who replaced them at the bottom.
Ian Hallam (52no) was the only home batsman to reach double figures then Faisal Javed cracked an unbeaten 53 for Spalding.
Market Deeping lost by 15 runs at Woodhall Spa, despite the efforts of captain David Sargeant (91) and opener Josh Smith (65).
Prasanna Jayawardene (110) was supported by Jack Timby (64) and Joe Irving (51).
Other results: Louth 183, Alford 141-9; Sleaford 243, Boston 246-4; Grantham 192-8, Lindum 176-9.
Fixtures (Saturday noon start): Bracebridge Heath v Boston, Grantham v Alford, Louth v Bourne, Market Deeping v Lindum, Sleaford v Grimsby, Spalding v Woodhall Spa.