Former leaders Accrington drop down to to third place after a 40 run defeat at Middleton.
Professional Gareth Severin top scored with 64 in Middleton's 225-6.
Openers Dawood Rahman (30) and Flynn Buckley (30) put on 66 before Buckley was caught by skipper Jacob Clarke off Asad Khan. Rahman followed at 72, caught by Graeme Sneddon off professional Jurie Snyman.
Severin and stand-in skipper Rehan Udwadia (46) put on 91 for the 3rd wicket before Severin was caught by Clarke off Snyman after hitting three sixes and two fours in his 62 ball knock.
Rhys Tierney (10) was caught by Snyman off Clarke at 182 and Addison Holland (5) was run out at 203.
Udwadia was also run out at 218 leaving Adam Fawcett (9 not out) and Tom Rutter (6 not out) unbeaten at the close.
Dale Highton took 5-38 to help bowl Accrington out for 185.
Tierney removed Sneddon (3) at 10 and Buckley picked up Jonny Dack (15) at 23.
Snyman and Clarke put Accrington back in the contest with a stand of 67 which was broken when Snyman was run out for 34.
Clarke (36) holed out to Rahman off Highton 3 runs later with Emile Haratbar falling in identical fashion without scoring after another run had been added.
Highton then removed Nathaniel Young (8) at 112, Kian Farnworth (12) at 115 and Asad Khan (13) at 149.
Noah Cronshaw (2) hung around for 19 balls, helping Ali Hasham add 29 for the 9th wicket.
Hasham's run a ball knock of 55 which included four sixes and two fours, helping Accrington claim two batting points, ended when he was caught by Rutter off Udwadia at 185.
The seconds also lost to Middleton.
Good knocks from Waleed Majeed (76) and Azmat Mehmood (75) helped the seconds post 198-4 but Middleton knocked off the runs in the 35th over.
