The youthful yellow-and-blacks inflicted a 26-run defeat on Cobo in a match they controlled largely from the off.
Openers Ben Maxton and Jack Birch gave Optis the ideal platform thanks to a first-wicket stand of 99 against an attack once again deprived of their main pace options.
Maxton hit five boundaries in his 45 from 39 balls while Birch finished as his side’s top-scorer with 56 that included a six and half-a-dozen fours. He faced 43 balls.
Tim Ravenscroft eventually made the breakthrough for Cobo by removing Maxton and soon added the scalp of Max Johnson before Dec Martel removed Birch.
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Left-arm spinner Dan Brown also picked up a wicket, that of Alex Bushell, but Charlie Clapham and Jake Swaisland joined forces in a crucial and unbroken fifth-wicket stand worth 36 to set Cobo a testing target of 174 for victory.
When Ravenscroft then miscued a pull shot from Peter Birch’s opening delivery of the reply only to see the ball land safely between two converging fielders, Optis must have wondered if luck was going to be against them.
However, the former pro was no so lucky in James Hudson’s first over when he toed another attempted pull straight up into the air and Ollie Clapham safely pounced the catch.
Buoyed by taking the big wicket, Hudson followed it up with those of Martel and Josh Butler in his next over to reduce Cobo to 25 for 3.
Although Ben Ferbrache and Jamie Nussbaumer, who made 32 and 52 respectively, managed something of a rebuild, Optimists never looked like losing, especially with Max Johnson conceding just 17 runs from his four overs in which he deservedly picked up the wicket of Nussbaumer.