Gubbins was initially joined in an opening partnership of 54 with Ali Orr (27) before Fletcha Middleton arrived to hit an unbeaten 35 from 24 balls in an unbroken second wicket stand of 108 in just 9.3 overs.
Fast bowler Nathan Barnwell was thrashed for 50 from his three overs – Gubbins twice hoicking him for six in an opening over costing 21 – and left-arm spinner Yousuf Majid’s three overs went for 31 as Gubbins and Middleton accelerated brutally towards the finish line.
Gubbins hit three sixes and 13 fours in all, while Middleton’s contribution was two sixes and four fours.
Earlier, 35-year-old Fuller finished with 4-34 after polishing off a Surrey innings that never got going and was in danger of complete implosion at 89-6 before keeper-batsman Josh Blake and bowlers James Taylor, Barnwell and Majid provided at least some lower order resistance in front of a near-5,000 crowd.
Blake was Surrey’s joint top-scorer with 22 alongside South Asian Cricket Academy graduate Nikhil Gorantla, who was Fuller’s first victim when he was excellently caught low down by Neal diving forward at mid-on in the 18th over.
That left Surrey 68-3 and Lumsden had already made his mark by then, first forcing Rory Burns to miscue a pull to his fourth ball – to be caught and bowled for 20 – and then seeing Adam Thomas chop on to his stumps for 12 in his third over.
At 16 years and 288 days, Lumsden bowled with genuine pace in just his second List A appearance and although there were a number of wild deliveries, including an intended bouncer that flew for four wides, he impressed across two spells in his 2-46 from 10 overs.
Even more impressive was 25-year old spinner Neal, who played two first-class matches for Leeds-Bradford MCCU in 2019, but only made the first of his previous four List A appearances earlier this month.
His 3-33 from 10 nicely-controlled overs now gives him nine wickets in the competition and he numbered the Surrey middle-order of Ben Foakes, Ollie Sykes and Cameron Steel as his victims.
Foakes mishit to long on for five, Sykes was brilliantly held by a diving Felix Organ at long on for seven and Steel drove tamely to short extra cover to go for five.
Blake’s 22 was ended by a fatal nibble at Fuller, Taylor (19) offered a few meaty blows before skying Scottish all-rounder Brandon McMullen to long on and Barnwell departed for 15 miscuing high to keeper Ben Mayes.
Majid was left 13 not out when No 11 Alex French fenced Fuller to slip to go for a fifth ball duck and all that remained was to see how quickly Hampshire’s top order could knock off the runs.
Thanks to Gubbins, Orr and Middleton the match was over by 4.10pm.
Match report supplied by ECB Reporters Network, supported by Rothesay
