Captain Andrew Strauss claimed England's defeat to Pakistan in the second Test in Abu Dhabi was the most painful of his career.
England were chasing just 145 for a victory in Abu Dhabi that would have levelled the three-Test series, but crumbled to 72 all out.
"I'd struggle to think of a loss that's hurt more than this," Strauss said.
"It was so disappointing after working so hard over the course of the game to put ourselves in a winning position."
He added: "Having done all that hard work, you need to go on and complete the job - and we just didn't play well enough individually and collectively.
"We've got to find ways of fighting back, and make sure we reconnect with all the good things we've done over the last couple of years."
England's bowlers performed creditably to twice bowl Pakistan out for less than 300, with Monty Panesar taking 6-62 in the second innings as Pakistan were dismissed for 214.
However, Abdur Rehman took 6-25 as England were shot out in only 36.1 overs on the fourth day at the Sheikh Zayed Stadium.
"The top order have got to take that on the chin and make sure it doesn't happen again," Strauss said.
"Sometimes you need to spend a bit of time at the wicket. There is always a balance between attack and defence.
"But it's important to acknowledge how well Pakistan played."
Spin accounted for 19 of the 20 England wickets to fall in the game, with the Decision Review System affecting the batsmen's approach to the slower bowlers.
"It has changed the dynamic of the game, to a certain extent," Strauss explained.
"In the old days, you could use your pad and bat together, but you cannot do that now as you feel very wary about playing across the line.
"But it is the same for both sides, and has helped our spinners to a huge extent as well.
"Ultimately, this was a great Test match, and a great Test match wicket, because it kept everybody interested.
"It is good for the game of Test cricket when things are happening and when both bowlers and batsmen are in the game."
The skipper had words of praise for slow left-armer Monty Panesar, who took seven wickets in his first Test since July 2009, bowling in tandem with fellow spinner Graeme Swann.
"Monty has always been a top-quality bowler - you know what you are going to get from him," Strauss said.
"He is going to bowl 99% of the balls in the right area. When there is a bit of turn, he can really exploit that, and it is fantastic to have him back and see his enthusiasm."
Strauss refused to rule out making changes to the team for the final Test in Dubai, which starts on Friday.
"Now is not the time to think about that," he said. "We will take in what happened, do that for the next day or two, and then come back strong in Dubai."