The leaders were going along nicely against Mudlarks with a 10-1 advantage, but an opposing trio of Fred Bradley, Derek Blow and George Foster hit back to level the scores at 11-all before Kestrels took a one-shot lead.
Mudlarks then stunned Kestrels by scooping six shots on the next end and held out for a 17-14 victory.
Kestrels also nearly blew it in their second game, letting an 11-5 lead slip to trail 13-11 against In A Minute, but finished strongly over the next four ends to win 21-13.
Dreamers stayed second with two wins, coming good at the end of the game to beat Wasps 14-11, and then earning a 18-4 victory over Wishfuls.
Third-placed Matelots won their only game 21-8 against Two Plus One, while Otters moved level on points after wins against Puffins (13-9) and Two Plus One (15-9).
* There was a change at the top of Group A of the Australian Pairs when George Foster and Terry Cornwall moved from third into first with a 19-10 win against Pete and Gill Fletcher who slipped a spot to third.
Previous leaders Tony Powell and Liz Draper were beaten 13-12 by Wendy Porter and David Wise and are one point off top spot.
Group B leaders Malcolm Pearce and Rachael Stanley are assured of a place in the end-of-season play-offs after a surprisingly simple victory over Richard Tyrell and Derek Tomlin who are the only pair within touching distance with games in hand.
Second-placed Ray and Sue Green lost out in a last-end thriller 11-10 to Barrie Scott and David Yates, while third-placed Fred and Jean Bradley were beaten 13-11 by Sue Gurbutt and Jane Scott.
* There was a change at the head of the Evening Pairs where just one point separates the top three.
Gary Boswell and Gill Fletcher hold first place after beating previous leaders Tina Reeson and Barrie Robinson, 20-12, who slip to third.
Barrie Scott and Ryan O’Connor pinched second place on shots difference after a comfortable win over Dave Gladding and Peter Neve.