Williams was 1-2 in sets down to Wayne Warren, but managed to level the match in the fourth set. The Welshman continued his comeback and claimed the fifth set with 3-1 to reach the last four.
Veenstra dropped one set against Derk Telnekes, as Telnekes hit a nice 130 checkout to win the first set. 'Flyers' took the second set after a decider, before taking the third set with 3-1. The fourth set went to Veenstra with 3-2 as he booked his place in the semi-finals.
Click here to find the prize fund breakdown for the Finder Darts Masters.
Jim Williams (90.40) 3-2 (89.97) Wayne Warren
Derk Telnekes (79.96) 1-3 (89.97) Richard Veenstra
Mark McGeeney v Scott Mitchell
Glen Durrant v Conan Whitehead
Levy Frauenfelder v Keane Barry
Williams/Warren vs Telnekes/Veenstra
McGeeney/Mitchell vs Durrant/Whitehead
Fallon Sherrock v Lisa Ashton
Winner SF1 vs Winner SF2