The derby clash at East Barton Avenue saw Corstorphine, with one league victory to their name in 2018, hosting a winless Watsonians outfit.
Batting first the visitors could only make 173 all out, skipper Ewan Chalmers top scoring with 48 and his younger brother Andrew making 28.
Callum Dutia was the pick of the home bowlers with 4-47 while skipper Joe Kinghorn-Gray weighed in with three wickets.
In reply Corstorphine were wobbling a bit at 28-2 early on, but pro Hammad Azam with 63 and Sam Flett, who was last week given his first ever Eastern Knights call-up, with 45 helped the home side to victory with five wickets and more than 20 overs to spare.
The victory leaves Corstorphine in mid-table with two wins from four since promotion, while Sonians now have a crucial home match with fellow strugglers Glenrothes this coming weekend.
Kinghorn-Gray said: “I am delighted that the team managed to bounce back from a disappointing loss at Aberdeenshire. This was a clinical performance with bat and ball and that was enough to see us over the line.
“Our pro Hammad Azam and overseas amateur Jacob Wood have slotted into the team well while it is great for our club to see Sam recognised with a Knights call-up.”
Grange gave James Stuart and George Thomas top team debuts while Andrew Appleton came in as they eased past Glenrothes by nine wickets in Fife.
Nick Farrar was the star man for Grange at Gilvenbank, the all-rounder taking four wickets and then blasting 82 not out opening the batting to see his side go top of the league.
Skipper Preston Mommsen took 2-19 from his 10 overs while all of the bowlers chipped in as the home side were all out for 139.
Farrar then saw them home with the bat, supported by 28 not out from Dylan Budge as they got over the line with nine wickets to spare.
Hayes van der Berg and Peter Ross were the men taking the plaudits for Heriot’s at Forthill against Forfarshire.
South African pro Van der Berg led the way for the reigning champions batting first in Broughty Ferry, his 107 being backed up by a first ever top flight hundred for Ross.
Ross’ 106 not out helped the visitors post 279-6 from their 50 overs and, even with their quality batting line-up, that was going to be tricky for Forfarshire to chase.
And so it proved, the home side making 253-8 with Elliot Ruthven the pick of the Heriot’s bowlers with 3-52.
After the 26 run win, a result that keeps Heriot’s unbeaten in all competitions in 2018, captain Keith Morton said: “We made the most of the good conditions with the bat to post a good total.
“They were two great innings by Hayes and Peter who both looked very controlled.
“Then our bowlers stuck to their task and delivered for us once again.”
Carlton and Stewart’s Melville both suffered defeats.
Michael Castle, on his league debut, made 49 and Parker Neame 43 as Carlton made 232 all out batting first against Arbroath at Grange Loan. Captain Ali Evans also chipped in with 41.
Evans and Omar Ahmad then both took two wickets, but Arbroath were always in control in their well executed run chase and they won by four wickets.
Michael Miller dug in for 38, but Stewart’s Melville could only muster 103 all out batting first at Aberdeenshire.
The hosts reached their victory target with no real issues.