England looked all but beaten when they stumbled to 117/5 in their pursuit of a 277-run target set by Pakistan at Old Trafford but captain Joe Root felt confident about his team's battling qualities.
"We knew it would take something special but after last summer it is very hard to stop believing. It's a real strong trait of ours," he said.
Almost a year on from Ben Stokes' heroic batting display to stun Australia in the 2019 Ashes at Headingley, Jos Buttler and Chris Woakes combined to deliver a counter-attacking display in a 139-run sixth-wicket stand.
Buttler (75) was trapped leg-before with 21 runs still required and the second new ball due, but Woakes (84 not out) stuck it out, edging the winning boundary down to third man to seal a famous victory.
"It was a brilliant chase. I couldn't be more proud of the lads," Root said.
"Jos, it shows the mental strength, to play that situation and manage different passages of it, calculating risks, manipulating the spinner, brilliant innings, and Chris was magnificent too.
"The more important thing is we back it up again, and keep learning, but the clarity with which they played shows the maturity of the group too."
With England losing four quick wickets after lunch, Woakes and Buttler had no choice but to reel in the target in one-day mode.
"It was good idea to take them on and put them under pressure," Woakes said. "He (Buttler) is one of the best white-ball players in the world - one of best run-chasers - and he showed why today."
The middle-order pair targeted the Pakistan spinners with drives, sweeps and reverse-sweeps as visiting captain Azhar Ali lost his reviews in desperation.
"When Buttler and Woakes came in and played their shots, they put us under pressure and we couldn't really answer them," Ali said.
"So credit to them, they outplayed us in that period. Maybe we were too late to bring fielders up.
"It's disappointing but not over yet, there are still two Tests to go."