The right-hander, who was the West End Redbacks’ leading one-day and first-class runscorer last summer, hit an unbeaten 159 from 136 balls against Northamptonshire which included 16 boundaries at a strike rate of 116.
Ferguson’s total was the biggest score by a Worcestershire player in any List A fixture against the Northants, surpassing a 120* by Graeme Hick 11 years ago.
It followed a sparkling debut from the 33-year-old where he notched a record-breaking 192 on debut for the Rapids.
Ferguson is now the only player with two scores beyond 150 in this year’s UK One-Day Cup.
The 34-run victory puts Worcestershire at the top of the North Group table with five wins from seven matches, including an undefeated record at home.
Ferguson will also represent Worcestershire in next month’s UK T20 Blast.