The Sri Lankan batsman was in sparkling form as he struck 13 boundaries and two sixes in his knock of 118.
The professional was given some excellent support from South African overseas ace Wian van Zyl and Edwin Moulton, who both struck 44.
Some late order hitting from Andrew Holdsworth (33 not out) enabled the hosts to close on a mammoth 263-4.
In reply, Garstang were always struggling to keep up with the required run rate although they battled on gamely.
Michael Wellings and Matthew Crowther each struck half-centuries but they were eventually all out for 203 in the 43rd over.
Fulwood and Broughton moved out of the relegation zone after thrashing rock bottom Preston at West Cliff.
Chris Brookes (3-10) was the pick of the bowlers for F&B as the hosts were routed for just 44 off 21.1 overs.
Professional Simon Kerrigan – who took two wickets – then smashed 29 off 25 balls as the visitors raced to victory for the loss of three wickets.
Leyland’s are up to fourth in the table, although they were indebted to Henry Thompson for their victory over Fleetwood at Broadwater.
The opener struck a brilliant century , hitting 15 fours and three sixes, to hold his side’s innings together as everyone else around him failed.
The visitors were dismissed for 158 with Alex Ryder taking 5-42.
Despite Thompson’s heroics, Fleetwood must have felt confident of chasing that total down but a superb all-round performance by Leyland’s bowlers saw them dismissed for a paltry 78. Will Jacques took 3-12.
Netherfield remain top of the table – but only four points clear of Blackpool, who arein second place.
The Cumbrians edged Morecambe in a high-scoring contest at Parkside Road.
An unbeaten knock 78 from John Huck and 63 from Bradley Earl enabled the hosts to declare on 263-6.
The visitors made a valiant attempt to chase down the total in reply. Professional Luke Jongwe hit 113 and Ryan Pearson 76 but Morecambe fell 14 runs short of victory as they closed on 249-8.
Blackpool were comfortable winners over St Annes at Stanley Park after knocking over the visitors for just 100. Matthew Siddall took 6-31 and Mohamed Nadeem scored 44.
In reply, the home side raced to victory off 23 overs for the loss of four wickets. Joshua Boyne was unbeaten on 27.
In the final match of the weekend, Barrow secured a winning draw over Penrith in a rain affected enounter at the Ernest Pass Memorial Ground.