Matt Milnes took a hat-trick and career-best figures of 7-38 as Yorkshire moved into pole position in a tight Group B battle for qualification for the knockout stages of the One-Day Cup.
Wins for the White Rose county, Somerset, Warwickshire and Middlesex narrowed the possible contenders down to four with one round to go, with Yorkshire looking strong favourites to go through.
In Group A, the picture cleared significantly with Worcestershire beating Leicestershire Foxes to become the second side after Gloucestershire to qualify, leaving Hampshire and Essex to battle for the final knockout berth.
The Foxes had slim qualification hopes going into the game but they were extinguished as they slipped to a 16-run defeat. The penultimate round of action also saw Nottinghamshire, Derbyshire and Surrey knocked out as Hampshire and Essex posted the wins that kept them in the hunt.
In Group B, defeats for Sussex, Durham and Kent saw their hopes of progression ended.
Yorkshire stayed top of Group B by beating Sussex, thanks in a large part to heroics from Milnes, who took two wickets in two balls in the fifth over and then bettered that with a hat-trick in the 45th over as the Hove hosts were restricted to 284-9.
A century from Pakistan international Imam-ul-Haq provided the foundation for a controlled Yorkshire reply along with a solid contribution from James Wharton (85), the pair breaking the back of the chase with a 196-run partnership for the second wicket.
Victory, achieved by six wickets and with 14 balls to spare, leaves Yorkshire as favourites to progress to the knockouts given a four-point lead over the chasing pack and a healthy net run-rate.
At Leicester, Brett D’Oliveira hit 107 from 105 balls in Worcestershire’s 328, Rishi Patel taking 5-65.
In reply, a fifth-wicket stand of 163 between Shan Masood (88) and Ben Cox (76) helped Leicestershire recover from 23-4. But the Foxes’ innings fell away again, with Ben Mike’s unbeaten 72 from 46 balls not enough to steer them home.