Paul have ended local rivals St Just's nine-year Vinter Cup unbeaten record with a five-wicket win at St Just cricket field.
Paul got off to a great start reducing St Just to 26-4 before Nick George and Iain McPeake shared an unbroken sixth-wicket partnership of 51 to take the hosts to 106-5 from their 20 overs.
For Paul, Kelvin Snell ended on 41 not out in their 108-5, after 21 had been required off three overs.
Paul will now face Truro or Camborne.
In the second quarter-final Falmouth beat Redruth by 25 runs.
The visitors made 138-6 before bowling out the hosts for 113 with three balls remaining.
Falmouth now play the winners of the Crofty/Holman v St Gluvias quarter-final in the last four.
The final two quarter-finals are scheduled for Thursday, 20 June.