Azhar Ali (76) and Fakhar Zaman (57) all but ended previously unbeaten tournament hosts England's slim hopes of victory with an opening stand of 118.
Hailing Pakistan's bowling attack, Morgan admitted that the Pakistan bowlers meant business and they were pretty good on the field.
England's Jonny Bairstow throws the ball while Pakistan bat during the ICC Champions Trophy semi-final.
"You are always comfortable with a partner who goes hard up front", Azhar said.
"One thing we didn't do was adapt to conditions, which I thought Pakistan did extremely well", said England captain Eoin Morgan.
Pakistan's more seasoned players like Shoaib Malik and Mohammad Hafeez are yet to fire in the tournament and have so far been overshadowed by the young performers. "Today was a ideal performance from all departments", said Azhar.
"I think it will have to evolve in whatever manner the game does over the next two years in the lead-in to the World Cup, but certainly I think we're moving in the right direction". Match-by-match Pakistan's game has come together after the hammering they took in their first match of the tournament against India. "It was a wonderful performance".
"We certainly weren't over-confident", Morgan said.
"We played very well".
"India match gone": Asked how self-belief had been restored following a defeat by India greeted with widespread condemnation back home, Sarfraz explained: "After the India match, we just motivated the guys". And now that they're in it, #Pakistan fans want a rematch against India. ODI cricket has followed a similar trend in the recent past, high scoring matches attract crowds and there aren't many plot twists, you go out there and just try to outscore the opposition. "Now we are in the final". "It was my first big event as captain".
That will have to wait at least another two years after their untypically meek performance on a slow, used pitch in Cardiff on Wednesday, when they lost their last eight wickets for 83 runs before Pakistan coasted to victory to book their place in this weekend's final at The Oval, where they will face India.
Morgan believes that experience, on the same strip prepared for Wednesday's match, played its part - and spelled out that England did not take unpredictable Pakistan lightly. I think going into today's game, knowing that we were going to play on a used wicket, potentially brought Pakistan's game closer to their home.