Batting first, Clydesdale posted a barely-adequate target of 206, with only Safyaan Sharif (35) and Andrew Scobie (31 not out) passing the 30 mark.
The Torrance House travellers enjoyed causing the maximum embarrassment to their hosts, racing to victory with five overs in hand.
The other southside clubs also lost in the latest round of the Scottish Cup.
At Shawholm, hosts Poloc batted first against Ayr, and never got going as wickets fell at regular intervals.
But the target of 168, with nearly three overs unused, was never likely to pose problems for the Ayr team, although Zaeem Mirza’ four wickets gave them a fright as they finished with only two wickets in hand.
At Albert Park, Weir’s allowed Drumpellier too much latitude, conceding 253 runs and taking just four of the visitors’ wickets the Weir’s batsmen were simply not up to the challenge, all out for 91 with 18 overs remaining.