Skipper Eoin Morgan said England's batting collapse in the third Twenty20 international was their worst performance in recent times after India inflicted a crushing defeat in the series decider in Bangalore.
Chasing 203 for victory, England's much-vaunted batting line-up imploded on Wednesday night, losing their last eight wickets for eight runs after being well set to push for victory.
Leg-spinner Yuzvendra Chahal's Twenty20 best of six for 25 combined with Jasprit Bumrah's three wickets ripped through the English middle and lower order, with five batsmen being dismissed without scoring.
"I can't put my finger on it. We haven't produced a batting performance as bad as that in two and a half years," Morgan told reporters at Bangalore's M Chinnaswamy Stadium.
"We pride ourselves on our batting and it's been our strong suit for a long time but our bowlers have outperformed our batters."
Since their meek exit in the group stage of the 2015 World Cup, England have been a team transformed in short-form cricket and reached the final of the World Twenty20 last year under Morgan's captaincy.
Their batting line-up is seen as their great strength, with some of the most powerful hitters in the game.
But after reaching 119 for two, England suffered a stunning collapse with Chahal taking the wickets of Morgan (40) and Joe Root (42) off consecutive deliveries.
The 26-year-old spinner, playing his sixth Twenty20 international, took another three wickets in his fourth over.
"We committed the cardinal sin of losing two in players in one over and the allowed India to build pressure. We weren't up to it at all. It's really disappointing," said Morgan.
"Take your hat off to India. They played well and put in a performance worthy of winning the series. We weren't good enough to win this series."
The defeat capped a miserable period in India for England, who lost the five-Test series 4-0 last year and went down 2-1 in both the subsequent one-day internationals and the Twenty20s this year.
England coach Trevor Bayliss acknowledged the team's inability to handle world-class spin, but insisted the visitors played "some pretty good cricket" at times during the ODI and Twenty20 series.
"We are certainly not world-class players of spin. We are mainly a young group making their way in international cricket," Bayliss told the BBC.
"Bit disappointing in the way we finished our series there, certainly doesn't reflect the type of cricket we've played here."
England are scheduled to tour West Indies for a three-match one-day international series next month ahead of hosting of the 50-over eight-team Champions Trophy in June.