Northamptonshire 217 for 6 (Cobb 58, Taylor 3-45) beat Gloucestershire 215 (Howell 80, Roderick 57, Crook 4-37, Stone 3-34) by four wickets

Steven Crook led an impressive Northamptonshire bowling display to keep his side in the race for a Royal London Cup quarter-final. Crook's 4 for 35 helped bowl Gloucestershire out for just 215 and despite a wobble, Northants got home by four wickets with nine overs to spare.

Victory for Northamptonshire at Headingley on Tuesday will see the Steelbacks through the quarter-finals. Gloucestershire will have another go at securing a home quarter-final at home to Surrey.

An opening stand of 80 between Josh Cobb and David Willey got the chase off to a solid start. Several moments of fortune, the chief of those Cobb bring dropped by Chris Dent at second slip on 16, aided their progress, but Cobb took the life to swat David Payne past mid-off and lift Craig Miles over mid-on; another boundary followed through cover point. He went to a second half-century in the competition from 68 balls but trying to find the shortest boundary on the ground in Miles Hammond's first over, picked out deep midwicket.

Cobb was the second wicket in a collapse of 3 for 6. Before Cobb's dismissal, there were two caught and bowled dismissals for off spinner Jack Taylor. First Ben Duckett and then Rob Keogh for a fourth-ball duck.

111 for 1 became 170 for 6 - a similar slide to those suffered throughout the competition but captain Alex Wakley was on hand to solidify the sloppiness and carefully steer his side home, a straight six off Dent the pick of his strokes in a unbeaten 31. He and Kyle Coetzer - playing for the first time in the competition this season - added 47 for the seventh wicket to settle any nerves.

"I had a bit of luck because it was my birthday," Josh Cobb said. "But we've made it hard in the last two games with the bat and we've spoke about taking the chance if we get another in what is effectively a final at Headingley.

"James Fuller's opening spell was one of the best we've faced in a long time and to come through that was a great effort. But we've bowled really well. Olly Stone bowled with real pace and Steven Crook was excellent again - the bowlers did the hard work for us."

The batting effort ensured another excellent display with the ball did not go to waste. Benny Howell and Gareth Roderick made steady half-centuries but there was precious little else for Gloucestershire who were blown away having won the toss and did well to posed 215 having been first 20 for 3 and then 140 for 7.

Howell and Roderick added 89 for the fourth wicket but, when well set and Roderick past fifty in 67 balls, Howell sent his partner back looking for a sharp single and Roderick was run-out for 57. It was a complete waste with Roderick finding his touch, twice lifting the off spin of Rob Keogh over mid-off - the first time all the way for six - and backing away to strike Azharullah twice through the covers for boundaries to bring up a third half-century in the competition.

Feeling guilty of his error no doubt, Howell build a considered knock of 80. Circumspect out of necessity, Howell steered Gloucestershire deeper into their innings to save them from disaster but not until James Fuller arrived at No. 9 did he find another game partner. 49 were added for the eighth wicket and Gloucestershire were at least able to push above 200.

They had been in danger of being fired out very cheaply. Two wickets in three balls from Olly Stone - a yorker to Will Tavare and a nip-backer to Geraint Jones - did the early damage before Crook carried his form over from a fine weekend against the Australians - a century backed up by wickets, too - with four wickets, all of them catches for wicketkeeper Ben Duckett.

He struck at the start of his first and second spells; initially coming on to dismiss Kieran Neoma-Barnett and then two balls into his third spell, James Fuller to break the second recovery act. Jack Taylor also edged behind trying to cut and Craig Miles became Crook's fourth wicket - his third four-wicket haul in List A cricket.

Gloucestershire coach Richard Dawson rued a sloppy performance: "We didn't start the game with a bang. We did well get our innings back but then another mistake cost us. It's easy to see where we messed up. We weren't at the races really. The first 10 overs with the ball we did well and could have taken couple of wickets but we didn't nail the first half with the bat."