Cornwall didn't so much tear up the record book as put it through the shredder when they demolished Buckinghamshire by nine wickets at Marlow yesterday.

Cornish openers David Roberts and Matt Robins were in imperious form in this Minor Counties Championship Knock-Out Cup fixture and launched a devastating assault against a team that reached the quarter-finals last season and are the reigning Minor Counties champions.

Buckinghamshire set their opponents a daunting 308 to win from 50 overs and then saw St Just's former Northamptonshire professional Roberts hammer 130 not out in partnership with Callington's Robins, who was dismissed for 143 a mere 20 short of the target. Buckinghamshire were shell-shocked as they trudged off the field with nine overs unused and Cornwall skipper Tom Sharp was equally awestruck by the feat.

"That was an unbelievable batting performance, quite brilliant," said Sharp, whose team are now well-placed to take one of the two qualifying places into the knock-out stage of the competition. "It's hard to remember them batting that well but they're great players and you know they're always capable of that sort of thing."

The two counties have not played each in any competition for 19 years and Buckinghamshire will sincerely hope for another long wait before they meet again. The 287-run partnership eclipsed the previous record 147 set by Gary Thomas (60) and Keith Parsons against Herefordshire at Truro last season, a record that had stood since 1983, with both batsmen eager to play their shots from the outset and punishing the home attack at will as an afternoon of torture dragged on for the Buckinghamshire bowlers.

Robins had hit 21 fours and one six from 122 deliveries by the time he was dismissed on 157 minutes, caught by Usman Arif off a Zahir Sher delivery. Roberts had been at the crease for 168 minutes by the time victory had been achieved and had struck 15 fours and one six off 121 deliveries faced.

Callington's Dan Davis had been padded up in the pavilion all afternoon waiting to go in at number three and had 17 to his name as he left the field with Roberts to the sporting applause of the home players and supporters.

"We were quite happy to sit in the pavilion and watch it all happening," said Sharp, who was scheduled to be next man in. "We said at lunchtime that if we had wickets in hand coming into the last 15 overs we'd have a chance but we did slightly better than that.

"We've got a week off now before we play Wales at St Austell so we'll be able to see how the land lies after the next round and we should be in a reasonable strong position. If it comes down to net run-rate we're not doing too badly."

Cornwall could not have expected such an emphatic victory after a less than impressive bowling display in which opener Matthew Eyles had hammered 139 before being caught by Chris Hunkin off Robins, with Paul Sawyer looking good for a century before he was run out on 96.

Cornwall had been hampered by the loss of opening bowler Alex Smeeth, who was only able to bowl three overs before retiring with a leg injuryand it was Kelvin Snell who was the best of the bowlers with three for 63 off seven overs.

Sharp however must have assumed his players faced an uphill struggle at half-time. He said: "We didn't bowl or field particularly well and at one stage they looked like getting 330 but Chris Hunkin bowled well in the middle and we stopped them getting that but it was still a big target."

That big target was made to look inadequate by the Cornish batting display that followed. Robins has been in prolific form in the Cornwall Premier League 50-50 competition this season following his move from Werrington while Roberts hit a century in a losing cause two weeks ago when Cornwall lost at Wiltshire in the Trophy.

Sharp was delighted that this time the efforts of the St Just playmaker earned greater reward and paid tribute to both batsmen. He said: "They both hit it to every part of the field and when they're in that sort of form they're very hard to bowl at, especially on a ground that's not all that big and with a quick outfield. It was an awesome display."