"Obviously, on their day, they (Pakistan) can beat any team in the world...They're very dangerous."
But Arthur was in no doubt of England's quality, saying: "They're a really good one-day unit with no apparent weaknesses."
England, however, are set to drop opener Jason Roy, whose latest low score in the victory over Australia last time out means he has now managed just 51 runs in eight ODI innings this season, and replace him with Jonny Bairstow.
Morgan, whose 87 together with Ben Stokes's 102 not out saw England recover from a top-order collapse against Australia, would not confirm England's XI on Tuesday.
But he signalled a change by saying: "We're getting to the business end of the tournament and we need to produce results."
Roy apart, England appear to have all bases covered as they go in search of their first major ODI title, with a long batting order and a balanced attack led by fast bowler Mark Wood.
"I think we've started brilliantly," said Morgan. "I hope we've not played our best cricket yet."
SQUADS: England Team: Jason Roy, Alex Hales, Joe Root, Eoin Morgan(c), Ben Stokes, Jos Buttler(wk), Moeen Ali, Steven Finn, Liam Plunkett, Mark Wood, Jake Ball, Jonny Bairstow, Sam Billings, Adil Rashid, David Willey
Pakistan Team: Sarfraz Khan (c and wk), Ahmed Shehzad, Azhar Ali, Babar Azam, Faheem Ashraf, Fakhar Zaman, Haris Sohail, Hasan Ali, Imad Wasim, Junaid Khan, Mohammed Amir, Mohammed Hafeez, Shadab Khan and Shoaib Malik.
Ben Stokeschampions trophy 2017England vs Pakistaneoin morganICC Champions Trophy 2017Jonny BairstowLive Cricket Scorelive scoreMohammad AmirSarfraz Ahmed
First Published: June 14, 2017, 9:17 AM IST