Vikram Solanki and Phil Hughes both hit centuries but Worcestershire still fell to a 12-run defeat to Lancashire on the Duckworth-Lewis method in their Clydesdale Bank 40 at Old Trafford.
After being invited to bat first the Royals' pair shared their county's highest-ever second-wicket partnership in List A cricket to underpin their total of 259-9.
Their 208 stand inside 32 overs helped Worcestershire recover from four one after Moeen Ali was trapped lbw by Sajid Mahmood.
Solanki led the way with 121 off 107 balls, including eight fours and five sixes, while Australian left-hander Hughes hit nine fours and two sixes in 104 off 111, following on from his 111 in their previous match against Middlesex.
But Worcestershire lost eight wickets for 47 runs in just 33 balls to slip from 212-1 and give the home side the momentum going into their chase, which was revised down to 131 off 19 overs after an hour and 25 minutes of rain.
Lancashire had reached 69-1 from 11.4 overs when the rain arrived thanks to a fourth successive half-century from former Pear Stephen Moore.
When play briefly resumed Moore added eight runs to be 60 from 52 balls as Lancashire reached 95-1 from 14.1 overs.
But more rain arrived to end the contest and lift the hosts up to second place in Group A. Croft also added an important unbeaten 19 off 14.
Ajmal Shahzad took three of four wickets to fall in the final over of the Worcestershire innings, including Hughes caught behind, Ben Scott trapped lbw and Alexei Kervezee caught at backward point off a leading edge.
Having bowled James Cameron in the 38th over, he finished with 4-51 from eight overs.
Worcestershire's late collapse meant the scoreboard had the strange look of having no batsmen in double figures aside from centurions Solanki and Hughes.
Despite some clean striking from the pair, they were happy to tick along without taking too many chances until the start of the batting powerplay with their side at 153-1 at the start of the 30th over.
Hughes hit Shahzad for four and six over mid-wicket off successive deliveries as he helped take 16 off the over and a total of 40 in the four overs.
Solanki hit the majority of his sixes down the ground, ranging between long-off and long-on, while Hughes targeted midwicket.
The pair's partnership beat the unbroken 204 shared between Tom Moody and Graeme Hick in a List A match against Zimbabwe at Bulawayo whilst on pre-season tour in 1991.
But it was not enough as Lancashire, whose only wicket to fall was Ashwell Prince bowled by Moeen, recovered to secure their third win from four.