An alarming batting collapse from 131-1 to 142-7 and a slow start with the ball proved decisive against stronger all-round opposition than Town normally face.
Chris Milner’s 60 and 40 from skipper David Clarke looked to have set Town up for an impressive 40-over total, but it required some late hitting from Mark Edwards (39no) and Karanpal Singh to get the hosts past the 200 mark.
But Cambridge enjoyed a flying start in reply and were never subsequently under any run-rate pressure as they cantered home with almost four overs to spare.
Town had beaten Rushden by five wickets in the Northants Premier Division 24 hours earlier after staging a couple of impressive fightbacks. Rushden lost their last five wickets for just seven runs as they were dismissed for 187, but, despite a splendid 63 from Josh Smith, Town required an unbroken sixth stand of 58 between Scott Howard (36) and Alex Mitchell (28) to get home. Smith also claimed four wickets.
Town were knocked off the top by Finedon though. They picked up 25 points for winning after batting first, five more than Town were awarded.
Bourne’s spectacular season continued with victory in the Lincs T20 qualifier at Market Deeping. They beat the hosts on run rate after an ill-timed shower and Woodhall Spa by 44 runs after a brilliant century from Pete Morgan.
Morgan struck six sixes and 10 fours in a 57-ball innings of 114 as Bourne piled up 196-3.
Bourne will now attend Finals Day at Sleaford next Saturday (July 10) when they face a semi-final against Lindum and possibly a final against either Bracebridge Heath or Grantham.
Ramsey suffered a dramatic batting collapse as they turned certain victory into defeat at Cambs Division One title challengers Histon. Excellence from Michael Cafferkey (96) and Ben Saunders (74) steered the Rams to 189-2 chasing 229, but they lost their last eight wickets for just 35 runs. Wisbech legend Gary Freaar smacked 105 and took three wickets in a comfortable win over Foxton. Stamford won a low-scoring game against St Giles and March were beaten by Cambridge seconds.
In Division Two Castor shot Huntingdon out for 28 to complete an 84-run win. Stuart Dockerill bagged 7-15 for Castor.
Ufford Park lost a tight game at Kimbolton by three wickets.
ECB CLUB CHAMPIONSHIP
Cambridge CC 205-5 (A. Bassingthwaigte 83no, K. Singh 2-42) beat Peterborough Town 204-9 (C. Milner 60, D. Clarke 40, M. Edwards 39no) by 5 wkts.
LINCS Winkworth T20 Cup
Bourne 68-3 (S. Evison 35) beat Market Deeping 132 (J. Smith 41, B. Diplock 3-23, M. Kidd 3-24) on run rate
Bourne 196-3 (P. Morgan 114no, J. Berry 42, S. Evison 33) beat Woodhall Spa 152 (T. Dixon 4-16, C. Cheer 2-22) by 44 runs.
Market Deeping 105-3 (J. Smith 38, Z. Manzoor 27no) beat Woodhall Spa 102 (J. Ghani 3-17, H. Niazi 2-14, J. Hook 2-16, S. Amir 2-26) by 7 wkts.
NORTHANTS PREMIER DIVISION
Peterborough Town 191-5 (J. Smith 63, S. Howard 36no, A. Mitchell 28no) beat Rushden 187 (J. Smith 4-24, R. Kendall 2-41) by 5 wkts.
CAMBS DIVISION ONE
Histon 229-9 (M. Cafferkey 4-37, S. Vallance 2-34) beat Ramsey 224 (M. Cafferkey 97, B. Saunders 78) by 5 runs
Cambridge 2nds 159-6 (P. Nightingale 2-33) beat March 156 (S. Rajaguru 40, A, George 36) by 4 wkts
Stamford 161-8 (B. Peck 32no) beat St Giles 137 (S. Chamberlain 4-19, S. Prentice 3-25) by 24 runs.
Wisbech 258-8 (G. Freear 105, J., Bowers 46, D. Haynes 41) beat Foxton 197 (A. Hooley 105, A. Palmer 4-41, G. Freear 3-50) by 61 runs.
CAMBS DIVISION TWO
Castor 112 (M. Wheat 32) beat Huntingdon 28 (S. Dockerill 7-15, S. Dunn 3-13) by 84 runs
Kimbolton 191-7 beat Ufford Park 187-9 by 3 wkts.