The 2011 National Club Champions, Shrewsbury, snatched victory from the jaws of defeat as they produced a remarkable recovery to beat Chorley by four runs.
The hosts started steadily after choosing to bat, but the run out of Will Parton sparked a flurry of wickets as Shrewsbury went from 46 without loss to 64 for four.
Captain Rob Foster and Stephen Barnard rebuilt but some disciplined Chorley bowling, especially by Chris Harty, offered few scoring opportunities and slowed the run rate.
After Foster fell, Barnard marshalled the tail but scoring continued to be difficult and the hosts could only reach 168 for eight from 45 overs.
In reply, Chorley opener Andrew Griffiths helped put the visitors in a strong position with a near run-a-ball 43 before being dismissed by Mike Barnard.
This brought Ian Dickinson to the crease and he combined with David Fisher to move the score onto 145 for one in the 38th over before Henry Blofield removed Dickinson for 36.
With Chorley requiring just 24 to win at a run-a-ball, the Barnard brothers produced an excellent bowling display to restrict the runs and apply pressure. There were two run-outs, including that of Fisher for 54, as Chorley could only make 164 for six.
Shrewsbury will host West Indian Cavaliers, who recorded a 96-run win over Liverpool & District League side Ormskirk, in the quarter-finals.
Batting first, the Cavaliers from the Nottinghamshire Premier League had ex-England batsman Usman Afzaal to thank as he hit 65 in a total of 237 for six.
Martyn Farrell bowled well to keep the runs down and Liam Hurt took three wickets, with the visitors feeling they had left a gettable target.
However, Akhil Patel had other ideas. The Cavaliers opening batsman shone with the ball, taking 6-27 from nine overs to help skittle out Ormskirk for 141 with nearly 10 overs to spare. Only Matthew Glayzer was able to score more than 20.
Ealing enjoyed a comfortable six-wicket win over Southern Premier League side and 2012 semi-finalists Havant to book a home draw in the quarter-finals.
Havant chose to bat in hot conditions and both Robert Green and Christopher Stone hit half-centuries as the hosts put on 240 for nine, ex-Middlesex player Chris Peploe the standout bowler with 3-33.
The Wilkin brothers then took to the hosts bowling attack. Oliver opened and hit a quickfire 38 from just 21 balls before Mylo took over and compiled a more patient 66 off 76, supported by 50 from Chris Wakefield, as Ealing reached their target with 19 balls to spare.
West of England Premier League leaders Bath will travel to Ealing after they secured a 50-run win from their trip to Cornwall against Werrington.
Batting first, Bath reached 220 for seven as captain James Campbell, Max O'Leary and James Brown all made forties. Andrew Smeeth was the pick of the hosts bowling attack as he took 4-52.
Werrington found it difficult to build partnerships in reply as all six Bath bowlers took wickets to dismiss the Cornwall Premier League leaders for 170.
East Anglian Premier League leaders Swardeston have reached the quarter-finals for the first time, having beat Middlesex League side Stanmore by three wickets.
Stanmore won the toss, chose to bat and reached 205 for nine. Steve Mehra top-scored with 36, while Michael Eccles’ 4-42 helped restrict the visitors’ batsmen.
The Norfolk side had Callum Taylor to thank as his unbeaten 89 from 90 balls underpinned a successful chase completed with three wickets in hand and six overs remaining.
Khawar Ali Kazmi produced his second successive match-winning performance in the National Club Championship as his all-round display helped guide Waltham to a 19-run win over runaway Kent Premier League leaders Hartley Country Club.
He hit 73 in Waltham's 236 for six before taking 4-52 in Hartley's reply. Hartley's Scott McKechnie hit 68 but it wasn't enough and the Essex side will face Swardeston in the last eight.
2006 and 2010 winners South Northumberland had the most comfortable win of the round as they beat Yorkshire Premier League side Doncaster Town by eight wickets.
The North East Premier League side bowled well to restrict their hosts to 183 for eight, Stephen Humble's 3-29 including the key wicket of James Stuart who hit 63.
Wicketkeeper Sam Jobson then opened for the visitors and hit 78 from 67 balls as South North reached their target with 13 overs to spare.
Barnt Green are the second Birmingham & District Premier League side in the last eight, along with Shrewsbury, after they beat Cheshire Premier League outfit Bowdon by 51 runs at Cherry Hill Road to earn a home tie against South North.
The hosts batted first and reached 223 for seven thanks largely to Richard Wilkinson's unbeaten 79. Chris Ashling became the competition’s leading wicket-taker with 15 when returning 2-44.
Andrew Sutton then returned an excellent analysis of 2-10 from nine overs as Bowdon struggled to keep up with the required run-rate, lost wickets at regular intervals and ended up being dismissed for 172.
For a full list of the results and scorecards from the last-16 matches, please go to http://ecb.play-cricket.com/scoreboard/results.asp. The quarter-finals, listed below, will be played on Sunday August 4.
Barnt Green v South Northumberland
Ealing v Bath
Shrewsbury v West Indian Cavaliers
Swardeston v Waltham
The semi-finals will be held on Sunday September 1 with the final on Sunday September 15 at Emirates Durham ICG.