The Blaze 189 for 1 (Beaumont 83, S Bryce 53*) beat Northern Diamonds 185 (Winfield-Hill 56, Munro 3-35) by nine wickets
Despite the absence of their ex-South Africa international Nadine De Klerk as well as their other two England stars, Nat Sciver-Brunt and Sarah Glenn, The Blaze rushed to victory in less than half of the 50 overs available to collect four points plus a bonus point and maintain their unbeaten record in the 2023 season, Sarah Bryce backing Beaumont up with an unbeaten 53 from 61 balls in an unbroken second-wicket stand of 156.
Diamonds conceded a shocking 37 runs in extras, including 25 wides.
With regular new-ball bowlers Grace Ballinger (injured) and De Klerk missing, The Blaze initially struggled to contain Winfield-Hill as Diamonds backed up their decision to bat first on what looked a good pitch with a brisk start. With the ball racing across a lightning fast outfield at the pretty Queen's Park ground, the England international hit seven of her nine boundaries in the first five overs.
Yet The Blaze quickly found a way to stem the runs, with McCarthy - her debut delayed because of ankle surgery - conceding only 12 in an tight five-over opening spell. McCarthy was unlucky to see Hollie Armitage dropped on four, but left-arm spinner Kirstie Gordon, back leading The Blaze after her England A stint, cashed in at the other end, having Sterre Kalis snapped up at slip for 11 before Armitage was caught at mid-off.
Winfield-Hill, fresh from an unbeaten 116 against South East Stars, completed a fourth fifty of this year's competition but was bowled by off-spinner Lucy Higham, who had also removed Emma Marlow via a thin edge to the keeper.
Diamonds were 131 for four at the halfway stage of their innings and lost two more wickets without further score as Munro returned at the pavilion end with two wickets in two balls, having the dangerous Bess Heath well caught at long leg for a 19-ball 25 before bowling Phoebe Turner for a golden duck.
Unable to build any momentum, the Diamonds lost Lizzie Scott to a Munro slower ball, after which McCarthy gained deserved reward as Leah Dobson (24 from 28 balls) was pouched on the square leg boundary and Katie Levick caught behind, leaving the visitors 147 for nine in the 33rd before Grace Hall and Jessica Woolston frustrated Blaze with a 13-over stand that added 38 more to the chase.
Nonetheless, with a required rate of under four runs an over to complete a fifth win of the season, The Blaze were comfortably placed at 62 for one after the ten powerplay overs, Marie Kelly the only casualty when she bottom-edged leg spinner Levick into her stumps.
Beaumont and Sarah Bryce needed only seven overs to rack up a fifty partnership, with the target down to less than 100 by the 14th over with opportunities to find the tree-lined boundary being offered all too frequently by the Diamonds attack, who were also guilty of handing their opponents a steady supply of gift runs in wides and leg-byes.
The England opener's half-century came off 49 balls soon after she had lofted a ball from Woolston back over the bowler's head for the first six of her two sixes with The Blaze looking to make sure the win came with the bonus point for recording a scoring rate of 1.25 or more times that of their opponent.
Fittingly, it was Beaumont who finished the job in the 25th over with her 11th four to go with the two sixes.