An excellent early break from Rhodri Gomer-Davies nearly put Luke Charteris in at the corner, and Ceri Sweeney hit the post with a penalty resulting from the home side's pressure.
With his first-ball he had Davies caught by Luke Sutton and with his second he repeated the trick to new man Steve Harmison, picking up his fifth wicket in capping a remarkable win.
Newport Gwent Dragons lock Luke Charteris is also a replacement after flying in to replace Davies in the squad after the Cardiff Blue chipped a bone in his neck against the Canucks.
But Anderson soon trapped Davies playing across the line, and Park nicked behind to give wicket-keeper Luke Sutton his fourth catch of five in the innings.