Colin Munro has helped Auckland through to last four of the Ford Trophy – and they will contest the first preliminary final against Central Districts at New Plymouth on Saturday.
Munro, who was Worcestershire's overseas player in the NatWest T20 Blast last summer, finished the group stages with 297 runs at an average of 59.40.
The 27-year-old played a key role in Auckland finishing runners-up to Central Districts with five wins and three draws from their eight games.
Otago and Northern Districts, who finished third and fourth respectively, will contest the second preliminary final on Saturday in Queenstown.
The third preliminary final will be staged on Wednesday with the overall final taking place on February 1.
Auckland went through despite losing their final group match by two wickets to Northern Districts at Mount Maunganui.
Munro made a quickfire 31 off 23 balls with two sixes and four fours batting at number five but Auckland were in deep trouble at 65-7 before recovering to 160 all out in 43.5 overs.
Northern Districts were also struggling at 42-3 and their eighth wicket went down with 11 runs still required but they managed to secure the win which booked their place in the play-offs.
Munro finished as Worcestershire's second highest run-scorer behind skipper Daryl Mitchell in the T20 Blast last summer.