The home side knew a win would see them leapfrog their opponents, and they now sit 19-points clear with a game in hand.
Horncastle needed less than 18 overs to work their way through the visitors’ batting order, Hykeham’s batsmen back in the pavilion with just 47 on the board, Jack Christopher (18) and Jason Emms (12) the only players to reach double figures.
Gareth Jones led the way with the ball, claiming eight victims for the loss of 16 runs.
Support came from William Broughton (1-3) and Tom Johnson (1-27).
Horncastle’s openers Rob Bee and Matthew Hodgkin clocked up the required runs at pace, with less than eight overs completed.
Hodgkin’s 26 included five fours, while Bee added a six and a four on his way to 19.
This week the Sunday Firsts travel to Heckington (1.30pm).
Horncastle’s Saturday side were beaten by 168 runs at Brigg Town in the Lincolnshire County League Fourth Division.
Liam Redmond (129 not out) and Matthew Bell (60) proved the difference as the hosts posted 241-9.
Gareth Jones caught and bowled Bell as he took four wickets for the loss of 55 runs.
Wickets were also taken by Lewis Lovegrove (3-27) and Ben Wilkinson (1-40).
Horncastle were dismissed for 73, Paul File (27), Jones (17) and Lovegrove (11) leading the way with the bat.
Horncastle sit fourth in the table.
On Saturday Horncastle travel to Haxey (1pm).