Nottinghamshire 445 for 8 (Lumb 184, Wessels 146, Cobb 3-53) beat Northamptonshire 425 (Kleinveldt 128, Rossington 97, Gurney 3-69) by 20 runs
Lumb and Wessels logged an opening stand of 342 in 39.2 overs for Nottinghamshire under cloudless blue skies in a Royal London One-Day Cup group match before the partnership was finally broken when Wessels fell to Stephen Crook for 146, lifting him to short third man.
Their stand beat the previous record in England - 318 amassed by Rahul Dravid and Sourav Ganguly against Sri Lanka in Taunton in the 1999 World Cup. The India pair left of a slew of records in their wake - at the time the stand was the highest in any limited-overs international.
Nottinghamshire went on to make 445 for 8 in their 50 overs. It was the second highest total in List A matches worldwide, beaten only by Surrey's 496 for 4 against Gloucestershire at The Oval in 2007.
Astonishingly, despite being stricken by injuries, Northants got within 20 runs under the Trent Bridge floodlights in a match that included an aggregate of 870 runs - another domestic record and only two runs short of the world record - and a barely credible 35 sixes.
Lumb said: "It was an incredible match and hats off to Northants, they came out and pushed us to the wire. What a great game of cricket for everyone who rocked up to Trent Bridge today.
"It was one of those days when you walk out there and the stars are all aligned and you have a day out. It was a bit like that for me and Riki and we were able to put on a great partnership. That's all we were trying to do, get the team off to a good start, and today we kept on going and going."
Lumb and Wessels did not quite manage to overhaul the highest List A stand of all time, finishing third on the all-time worldwide list.
The record was set in February last year when Chris Gayle and Marlon Samuels took 372 off the Zimbabwe attack at Manuka Oval in the 2015 World Cup.
Lumb scored 184, making his runs from 150 deliveries, with 21 fours and six sixes, and Wessels hit 146 from 97 balls, with 14 fours and eight maximums, with both players reaching their highest one-day scores.
Lumb's fifth one-day ton was his first since scoring 106 on his England ODI debut in Antigua in 2014 and his first in domestic cricket since 2009. His 184 is also a county record, bettering the unbeaten 167 made by Paul Johnson in 1993. He also left to a standing ovation after being bowled by Sanderson, trying to deflect the bowler down to fine leg.
Neither opener offered a clear chance, although one or two mishits fell harmlessly into the outfield and a couple of run out opportunities went begging. That said, both batsmen deserved any good fortune that was going, due to their cleanness of their ball striking.
Nottinghamshire, easily surpassing their previous highest total of 368 for 2 made against Middlesex two years ago, predictably emerged victorious but Northants regained some kudos by amassing 425 in reply to lose by a much smaller margin than most would have assumed would be the case.
Northants' spirited retort was all the more remarkable considering that they were handicapped by a shoulder injury to Richard Levi, which meant he didn't bat until No 11. Veteran South African Rory Kleinveldt, nursing a calf injury, also batted with a runner and almost helped the visitors pull of a stunning run chase.
He hit 128 from only 63 balls, smashing 10 fours and nine sixes to put Notts under real pressure, all after Adam Rossington had made 97 at the top of the order.
Kleinveldt's incredible innings came to an end when he was superbly caught in the deep by sub fielder Anuj Dal, who had spent the day playing for Nottinghamshire's Second XI at Hinckley, against Leicestershire.
Dal also caught Graeme White for 40, leaving 21 required from the final two overs but Harry Gurney kept his nerve to bowl Levi in the penultimate over.
David Ripley, Northants' head coach, said: "I've never seen anything like it. Obviously it wasn't a game for the bowlers - on both sides. It was a great run chase from us, I don't think I've ever come across such a dangerous score that's been put in front of us and come so close. We're very disappointed, but we are very proud of the way we chased."