Captain Eoin Morgan felt a poor umpiring decision in the final over cost England victory over India in their second Twenty20 international.
Joe Root was given out lbw to the first ball of Jasprit Bumrah's last over despite him having edged the delivery.
England then failed to get the eight runs they needed, falling to a five-run defeat that levelled the series.
"That decision didn't go our way and it swung momentum in the opposition's favour," Morgan told BBC Sport.
"It has a huge effect, particularly on this wicket, where coming in and starting is extremely difficult."
Morgan later said England would by making their views known to match referee Andy Pycroft.
"We have an opportunity to do so before the next game. There's always feedback given through the match referee on our report," he said.
Root was on 38 when he was given out by Indian umpire Chettithody Shamshuddin at the start of what was a superb final over by Bumrah, who went for just two runs to end the match with figures of 2-20 from his four overs.
Morgan admitted to Sky Sports after Sunday's game in Nagpur that he would have been "fuming" had the decision against Root come in a big game, such as the World Cup.
Another poor decision by Shamshuddin - who is on the International Cricket Council's second-tier international panel of umpires - went against England earlier in the game when Virat Kohli survived an lbw appeal from Chris Jordan, when replays suggested the ball would have gone on to hit the stumps.
With the Decision Review System not in use during the T20 series, England had no way of challenging the decision, and the India captain went on to add a further 14 runs.
"That was disappointing as well," admitted Morgan. "but I don't think that was what cost us the game as we were in a commanding position throughout.
"I would probably say the decision that didn't go our way at the start of the 20th cost us a lot more."
Morgan said it was "a concern" that DRS was not in use, adding: "There is as much on the line as there is in a Test or a one-day match, so no reason why it shouldn't be used."
England had restricted India to 144-8 in Nagpur, with spinner Moeen Ali (1-20) and seamer Jordan (3-22) particularly impressive with the ball.
However, despite partnerships of 52 between Root and Ben Stokes, and 43 between the former and Morgan, India's bowlers came out on top with seamers Bumrah and Ashish Nehra (3-28) and spinner Amit Mishra (1-25) excelling.
"It is definitely one that has got away," said Morgan. "We commanded the game pretty much from the first ball. Our bowlers did a great job again and backed up their previous performance in the last game. On a wicket that favoured India more than us, we stepped up to the plate.
"In the chase, the run rate never got away from us and we managed to squeeze some partnerships together.
"Going in to the final over, you should be winning those games nine times out of 10."
The deciding game of the three-match series is in Bangalore on Wednesday.