Oliver Halion became the third Worcestershire Academy player to hit a hundred in the ECB Under-18 County Championship match with Cricket Wales at Abergavenny.
Halion emulated Henry Cullen and Ollie Walker, and Worcestershire are strongly placed to secure a successive victory in the competition on the final day.
Cricket Wales will resume on 30-1 on Thursday morning after Worcestershire captain, Joe Stanley, set them a mammoth 513 to win.
The home side were bowled out for 143 in their first innings – a deficit of 288 – with Ben Parker taking one more wicket to complete a five-for.
He ended with figures of 15-5-38-5 and there were two wickets on day two for spinner Olly Davidson (8.5-2-18-2), including top scorer Ollie Rayner (54).
Reeve Evitts (12-1-17-1) and Cameron Jones (8-1-22-1) were the other wicket-takers.
Stanley did not enforce the follow on, despite such a sizeable first innings advantage, and opener Halion took advantage to complete a 131-ball century with 10 fours.
He shared in stands of 46 with Jack Home (17), 56 with Evitts (24) and an unbroken 122 in 21 overs with Jones whose unbeaten 60 from 66 deliveries included one six and seven boundaries.
Worcestershire declared on 224-2 from 49 overs and Walker made a breakthrough before the close of play after 20 overs of Cricket Wales second innings.