England claimed their first international win since August in farcical circumstances when the West Indies miscalculated the Duckworth-Lewis target at the end of the opening one-dayer in Guyana on Friday.
West Indies, chasing England's 50-over total of 270 for seven, were offered the chance to go off due to rain and bad light and their Australian coach John Dyson beckoned the batsmen off the field.
However, the hosts were one run short of the Duckworth-Lewis target, the method used to calculate results when the full overs are unused, and with no opportunity to return to the field England were declared winners with West Indies on 244 for seven from 46.2 overs.
Dyson left his seat in the pavilion to consult match referee Javagal Srinath and England were soon celebrating their first win since a one-day victory over South Africa at Lord's.
"I was on the wrong column (on the sheet) ... I thought we were ahead of Duckworth-Lewis but in fact we were behind by one run," Dyson told Sky Sports television.
"There was a lot of noise going on and it was my responsibility, so that was it.
DYSON'S MISTAKE
"I accept responsibility for it and I've apologised to the team and that's all I can do. It was my mistake.
"It was getting dark and it would have been nice to have been ahead by one run," added Dyson.
England captain Andrew Strauss appeared confident as his side walked off the field.
"We looked at the sheet and it seemed to suggest we were one run ahead," said Strauss.
"When the batsmen walked off we were pretty confident we had won. Everyone in our support staff was 100 percent certain we had won and there were some pretty good celebrations in the changing room," added a grinning Strauss.
Earlier, England posted a challenging total thanks to a smart 43 off 62 balls from opener Ravi Bopara and good work in the middle-order from Paul Collingwood (69) and Owais Shah (62).
West Indies, in reply, lost skipper Chris Gayle for two before Lendl Simmons (62) and Ramnaresh Sarwan (57) put on 125 for the second wicket at a steady pace.
The game appeared to turn in the home team's favour when Shivnarine Chanderpaul cracked paceman Steve Harmison for 26 (five fours and a six) in one over.
It was back in the balance though after Chanderpaul was dismissed for 46 and hard-hitting Kieron Pollard fell for 42.
Stuart Broad grabbed his third wicket when he trapped Denesh Ramdin leg before for 11 with the second ball of the 47th over.
Before the new batsman could take strike the light was offered and the crowd were left bemused and West Indies embarrassed by their mistake.
The second game in the five-match series is in Georgetown on Sunday.
Scorecard
England:
A. Strauss c Bravo b Powell 15
R. Bopara lbw b Miller 43
K. Pietersen c Powell b Bravo 17
O. Shah c Ramdin b Bravo 62
P. Collingwood c Bravo b Pollard 69
D. Mascarenhas lbw b Pollard 0
M. Prior not out 26
S. Broad run out 8
G. Batty not out 2
Extras: (lb 4, w 23, nb 1) 28
Total: (seven wickets; 50 overs) 270
Fall of wickets: 1-28, 2-64, 3-117, 4-215, 5-216, 6-243, 7-263.
Did not bat: S. Harmison, J. Anderson
Bowling: D.Powell 5-0-27-1, F.Edwards 5-0-23-0, D.Bravo 10-0-65-2 (1nb), D.Sammy 10-0-43-0, N.Miller 9-0-48-1, K.Pollard 8-0-46-2, C.Gayle 3-0-14-0
West Indies:
C. Gayle lbw b Broad 2
L. Simmons c Anderson b Batty 62
R. Sarwan c Strauss b Collingwood 57
S. Chanderpaul c Strauss b Broad 46
K. Pollard c Harmison b Anderson 42
D. Bravo c Bopara b Anderson 1
D. Ramdin lbw b Broad 11
D. Sammy not out 0
Extras: (b 5, lb 4, w 14) 23
Total: (for seven wickets; 46.2 overs) 244
Fall of wickets: 1-6, 2-131, 3-152, 4-212, 5-213, 6-242, 7-244.
Did not bat: N. Miller, F. Edwards, D. Powell.
Bowling: S.Broad 9.2-2-41-3, J.Anderson 8-0-39-2, S.Harmison 7-0-51-0, D.Mascarenhas 8-0-33-0, G.Batty 7-0-34-1, P.Collingwood 7-0-37-1
Result: England beat West Indies by one run on Duckworth-Lewis method.