The 16-year-old from Drogheda had the bit between his teeth on the Kingsbury Packaging Kawasaki ZX-6R as he won the opening race by two seconds from Jason Lynn on the Walter Bell Suzuki, with Nikki Coates – winner of the David Wood Trophy for the past two seasons – finishing in third place. Coates was forced to switch to his brother's Yamaha R6 following a crash in qualifying, damaging his regular KP Kawasaki.
Clifford secured the silverware with another strong ride in race two at the Co Down track, crossing the line with 1.3 seconds in hand over Robert Kennedy with Lynn returning to the podium again in third.
Ross Patterson finished in fourth place ahead of Coates, who lost out in his bid to secure the Davy Wood Trophy for a third successive year.
In the Irish Superbike class, Bangor’s Robert English also notched up a double on the IFS Global Logistics Yamaha R1.
English, who is on course to win the Mondello Masters Championship in October, had 2.5 seconds in hand over Coates in race one as Charles Stuart – a winner at the ISB meeting at Kirkistown earlier this month – completed the top three.
Gerard Kinghan, Michael Sweeney and Gareth Keys rounded out the top six.
In race two, English completed his brace on the R1 by an extended margin of 4.3 seconds over Coates, with Kinghan getting the better of Stuart to seal the last position on the rostrum.