Iqbal hit an unbeaten 125, with Matthew Micklethwaite adding 40 as Cayton reached a useful 235-9. R Kirby taking four wickets and Ben Gregory bagging three.
Rikki Lawrence (80), James McMillan (58) and John Precious (43) made sure that Iqbal's efforts were in vain, with Muston reaching 236-4.
Scalby 3rds' Darrell Morley was in fine bowling form in the win by 82 runs against Scarborough 3rds.
Scarborough looked to be in with a shout at lunch, as Kieran Rutter's 4-24 and Andy Exton's 3-26 took out Scalby by 146, James Wainwright and Nathan Barber both scoring 40, while Luke Howland hit 31.
Morley took control at the resumption though, taking four wickets for five runs as Scarborough were gunned down for 64.
Wold Newton 2nds beat Filey 2nds by three wickets.
Mick Blythe hit 55 for Filey, but 4-25 from Gordon Taylor and 3-31 from Matthew Atkinson ended their change on 116, a score that Newton passed with three wickets left intact.
Scarborough RUFC conceded their game against Ravenscar 2nds.
Brompton 2nds were in impressive bowling form as they beat Malton & Old Malton 4ths by nine wickets in Division Four West.
John Sims was Malton's top scorer with 26 in Malton's 50, which was brought to a swift conclusion by Phil Holden's 4-20 and Craig Mudd's 3-1.
Chris Suggitt completed the job for Brompton with an unbeaten 31.
Ganton 2nds beat Forge Valley 3rds by 75 runs.
Dan Readon (62), Richard Horsman (57) and Freddie Bradley (21) scored the runs in Ganton's 181, Maclay Arnott and John Flinton both taking three wickets.
Eric Hall gave Valley some hope with 75, but Rob Bradley's 5-34 and Freddie Bradley's 4-17 sealed the victory for Ganton.
Pickering 4ths conceded their game against Wykeham 3rds.
In Division Three, Muston made light work of their six-wicket win against Ravenscar.
Brian Anderson's 3-9 and Scott Orange's 3-20 took out Ravenscar for 34.
Will Warwick bagged 3-11 in the reply, but Muston still completed their afternoon's work.
Forge Valley 2nds toppled Flamborough by five wickets.
Sean Pinder took 4-8 and Aaron Fox 4-13 to end Flamborough's innings on 79.
George Moyes' 3-26 put the pressure on the Valley line-up, but Christian Reddish's 53 was enough to lead them home.
Cloughton 2nds saw off Nawton Grange 2nds in comfortable fashion by nine wickets.
Ben Mason took 4-26 as Grange were dismissed for 92, before Mark Pryce's 4 not out and Tom Owenson's 26 wrapped things up.
Mulgrave 2nds took out Heslerton 2nds by 133 runs.
Nick Gibson (57no), Simon Kipling (47), Luke Spenceley (41) and Ben Duell (29) led Mulgrave to 227-6, Jake Sarup taking three of the wickets.
Duell's 3-18 and Dom Ingham's 4-17 completed things, though Dave Bointon's 40 kept Heslerton in it for a time.
There was no result received for the game between Snainton and Flixton 3rds, so Snainton have been fined £20.