Durham 260 for 7 (Richardson 72*, Lees 55) beat Derbyshire 255 for 8 (Critchley 49*, Lace 48) by three wickets
Durham made it three wins in a row at home in the Royal London One-Day Cup by defeating Derbyshire by three wickets at Emirates Riverside.
The hosts restricted Derbyshire to 255 for 8 from their 50 overs due to tight bowling from Ben Raine and James Weighell, who claimed two wickets apiece. Matt Critchley and Tom Lace led the way with the for the visitors, although neither batsman was able to pass fifty.
Durham were measured for the majority of their run chase, despite losing an early wicket. Alex Lees made 55, scoring his third half-century in a row. Michael Richardson (72 not out) saw his side over the line, upping the ante with five sixes to secure the victory for the hosts, leaving them in a strong position in the north group after five matches.
Derbyshire openers Luis Reece and Billy Godleman were prevented from scoring freely, which forced a mistake by Reece as he pulled a delivery from Weighell straight to Graham Clark. Godleman had made three centuries in a row, but his outstanding run was ended when he was caught down the legside for 23 off a delivery from Weighell.
Wayne Madsen looked in prime touch, dispatching two sixes over the rope. However, the arrival of Liam Trevaskis was to end his innings, bowling the South African for 38. Alex Hughes then became the first victim of Scott Steel in List A cricket, slicing the ball straight to Brydon Carse at backward point.
Leus du Plooy and Lace were able to stem the tide. The two players reached their fifty partnership from 52 balls, guiding Derbyshire past 150 in the process. Ben Raine ended their stand as du Plooy smashed an attempted pull straight to Lees for 32, leaving the visitors five down for 157.
However, Lace continued his impressive knock, and having already reached his highest List A score, the 20-year-old was on course for a fifty before he edged a Salisbury delivery behind to Cameron Bancroft.
Derbyshire were in need of a late surge from the lower order. Critchley provided the power, blasting three sixes in his unbeaten innings of 49 that allowed the visitors to post their highest List A total at Emirates Riverside.
Clark lasted just two deliveries into Durham's reply, slicing a ball from Sam Conners up in the air for Lace to claim with ease. Steel responded to kick-start the innings with a flurry of boundaries. He and Lees put on fifty in 55 deliveries before Steel was run out by a great throw from Conners from short fine leg to the bowler's end for 32.
Lees built his innings steadily with Bancroft before he upped the ante with three boundaries off a Reece over, bringing up the hundred for Durham and the fifty partnership with his skipper. Lees notched his third List A half-century on the bounce before giving his wicket away for 55 tamely driving a Ravi Rampaul delivery to Conners.
Rampaul then claimed the major scalp of Bancroft, who edged an attempted hook behind to Harvey Hosein for 45.
Richardson and Jack Burnham were able to calm the nerves for the home side, establishing a fifty partnership. Du Plooy had a huge opportunity to break the stand when Burnham skied a Critchley delivery straight to square leg, but the South African shelled the simple catch.
Burnham capitalised on his second chance, blasting two huge sixes to take his team within touching distance, although he fell for 45 to Lace. There was still time for Trevaskis and Carse to be dismissed before Richardson took control to blast Durham over the line, earning their fourth win in five games in the competition.