Derbyshire 203 for 6 (Lamb 63*) beat Northamptonshire 201 (Procter 39, Conners 3-32) by four wickets
Battling an injured back, Lamb faced 82 balls as Derbyshire struggled to force the pace on an increasingly sluggish pitch with just four boundaries coming in the first 37 overs of the chase.
After three wickets fell in 10 overs, Lamb combined with Brooke Guest in a stand of 77 in 18.2 overs. For most of that time, the pair looked comfortable, but were unable to locate the boundary ropes.
Lamb though began to accelerate with the Falcons needing 59 off the last 10 overs and reduced the target further to 26 from the last 30 balls. Joined by a proactive Anuj Dal (20) the pair took the visitors to within 21 of their target.
With Luke Procter conceding just one run off the 46th and Dal caught off Ben Sanderson with 20 balls remaining, the momentum shifted slightly back towards Northamptonshire.
Alex Thomson though hit Taylor down the ground for four, leaving Derbyshire needing 10 off the last two overs. Lamb and Thomson made sure the final over was not needed as both smashed Sanderson for four.
Defeat ends Northamptonshire’s hopes of qualifying for the knockout stages of this year’s tournament.