Narrow victories over two of their main rivals kept Yorkies top of the Louth Indoor Bowls Club Morning Triples League on shots difference.
They came good late in their game against Highgate Wanderers to turn a 12-10 deficit into a 14-12 lead and survived the last end to win 14-13.
The Yorkies were also given a tough time against The Jays, and again survived the last end to win 9-8, having led 9-5, to extend their winning run to nine games.
Highgate also lost their other game 16-9 to Two Plus One and slipped one place to third. Magpies took full advantage to go second by winning their two games.
They eased to a 20-7 win against Wasps and then beat Mudlarks 18-10 to stay level on points with the leaders and four points ahead of Highgate who have a game in hand.
Despite beating Hornets 21-4 The Jays have also slipped off the pace, but are not out of the chase. Two Plus One have a six-game winning run after beating Dreamers 16-10 and moved up to fifth, six points adrift of fourth spot.
In the Australian Pairs, Tony Powell and Liz Draper were relieved to emerge from a tough game against Ken and Sheila Webster with a 15-12 win.
They stay top of Group A on shots difference from Brian and Bernice Culham who had a more comfortable 17-9 victory over Brian Paffey and Chas Dewar.
No problems for the top two in Group B who enjoyed easy wins. Paul Hayman and Ian Bertram cruised to a 28-9 success over Jane Scott and Lorraine Evans. They stay two points clear of John Williams and Joan Foster who beat Jim Brennan and Sally Brown 23-4.
At the end of the season the winning pair in each group will play off to determine the overall champions.