Hosting Boston, Louth pulled off an aggregate shots victory of 118 against 67.
The quartet of Colin and Carol Smith, and Mike and Gill Leverton provided the best winning margin of the five rinks with a 29-10 victory.
The match win put the team top of Division One, three points ahead of Spalding who have played one game more.
* In the club’s leagues the last remaining unbeaten record has fallen by the wayside.
After 10 wins and a draw in Division Three of the Friday Mixed Pairs League, Sally and Barry Coultas lost for the first time when edged out 15-14 by Sue Page and Mike Catlow.
And to rub salt in the wound the Coultas pair also lost later the same day when playing a game in hand, going down 12-8 against Barry and Ros Toyn.
Page and Catlow now top the table by one point, but the Coultas’ still have a game in hand.
* APS are just one game away from clinching the Evening Fours title after beating Questors 28-7 to maintain their 10-point advantage over Fast Shippers who beat third-placed Roundheads 22-3.
* In the Ladies’ Triples League, current leaders Canaries are guaranteed a top-two finish after their 20-11 win over third-placed Follies put them six points clear of Jaytones who were held 18-18 by Tyros.
* The Tuesday Mixed Pairs has developed into a husband and wife battle, with Tina Reeson and Tony Musson topping the table, two points ahead of Simon Reeson and Gill Leverton.
But the gap could have been four points had Tina and Tony not lost 21-19 against Sylvia Stainton and Mally Hewson, while Simon and Gill won 18-10 against Sue Gurbutt and Robin Barrow.