Hampshire 295 for 8 (Weatherley 93, Gubbins 62) defeated Derbyshire 152 (Guest 44, Kelly 5-19) by 143 runs
In a commanding performance, Dominic Kelly claimed Hampshire's first List A hat-trick since 1981 and secured his first professional five-wicket haul, leading to a decisive 143-run triumph over Derbyshire in the Metro Bank One Day Cup.
The 18-year-old pacer dismissed Zak Chappell, Harry Moore, and Daryl Dupavillon, becoming the third Hampshire bowler to achieve a hat-trick, following John Rice in 1975 and Malcolm Marshall in 1981.
Joe Weatherley set the tone for the victory with a commanding 93, supported by Nick Gubbins' half-century, the pair adding 113 runs to propel Hampshire to 295.
Apart from Brooke Guest's 44, Derbyshire struggled in their chase before Kelly's sensational spell sealed their fate.
Hampshire, last year's finalists, ended their Utilita Bowl matches with a perfect record, positioning them well for the knockout stages, while Derbyshire faced their second defeat.
In Derbyshire's first visit to the Utilita Bowl in a decade, they opted to bowl first. Despite their accuracy, they managed to restrict Hampshire to 32 runs in the initial 10 overs.
Hampshire's top order, which had previously underperformed in the One Day Cup, rose to the occasion with a patient approach, laying a solid foundation for an aggressive finish.
Fletcha Middleton contributed 30 of the first 44 runs, partnering with Weatherley, before a top-edge off Daryn Dupavillon gave Derbyshire their first breakthrough. This led to a controlled 113-run partnership between Weatherley and Nick Gubbins, although reaching a par score of 280 seemed distant.
Weatherley, currently signed with the Brave in The Hundred but allowed to play for Hampshire due to limited action, showcased his skills by smoothly transitioning through gears, reaching his seventh List A fifty in 88 balls and accelerating to 93.
Gubbins complemented Weatherley by steadily increasing the runs, achieving his 59-ball half-century as Hampshire's slow start transformed into a more aggressive innings.
Despite losing wickets regularly in the latter part of the innings, Hampshire managed to amass 85 runs in the final 10 overs, reaching their highest List A total against Derbyshire.
In their chase, Derbyshire never found momentum, especially after Luis Reece was controversially caught behind in the third ball. Matt Lamb needed a runner before being caught off a top edge, David Lloyd edged a Brad Wheal delivery behind, and Anuj Dal was bowled by Kelly’s pace.
Brooke Guest showed promise with his timing, particularly with back-to-back offside sixes off Felix Organ, but a mix-up with Samit Patel led to his dismissal. Ross Whiteley soon followed, hitting to deep square leg.
Kelly then ended Hampshire’s 43-year wait for a hat-trick by dismissing Chappell, Moore, and Dupavillon in quick succession, sealing the emphatic victory.