'Below par' England were outfielded - Morgan
Eoin Morgan accepted England's fielding was not good enough as the Cricket World Cup hosts and favourites lost by 14 runs against Pakistan.
Hopes of a title challenge had been boosted by England's opening win against South Africa, yet they failed to build on that result as a big run chase fell short at Trent Bridge on Monday.
Joe Root (107) and Jos Buttler (103) both hit centuries, but Pakistan's total of 348-8 proved beyond them.
Captain Morgan suggested England lost up to 20 runs through poor fielding in the Pakistan innings and believes that is what cost his side.
"I thought we were outfielded today. It was probably the difference between the sides," he said in the post-match presentation.
"Our performance is going to go up and down throughout the tournament with the bat and with the ball, but our fielding has to remain a constant throughout the side.
"I thought it was well below par today and probably cost us 15 or 20 runs."
Morgan still felt England could have reached their victory target had his batsmen found their groove earlier.
"Trent Bridge is a very high-scoring ground," he said. "The wicket was very good, the outfield was absolutely rapid, and we felt that, if we got partnerships going, 350 was certainly within our grasp.
"Losing early wickets is not ideal, but certainly Joe and Jos kept us in the game until the mid-40th over, which is great.
"If we'd got a little bit of a partnership going earlier on in the innings, potentially we could have got over the line."
Pakistan had lost 11 consecutive ODIs before this victory, yet Mohammad Hafeez, who made 84 off 62 balls, insisted their confidence was never affected.
"Everyone was believing that we could do this, that we could win the games," he said. "We were playing very good cricket but we were not winning the crucial stages of the game.
"In the performance today, everyone chipped in, everyone gave everything required in the situation."
Hafeez added: "We were all very confident. We practised yesterday very well and we had a good meeting together. We knew we needed one winning performance from one person and then everybody else had to contribute accordingly."