Cape Town - New South African one-day captain Quinton de Kock won the toss and decided to bowl in the first one-day international against World Cup champions England at Newlands on Tuesday.
Both teams included two new caps in their first outing since the World Cup in July, although all four debutants have previously appeared in Twenty20 internationals.
South Africa included all-rounder Jon-Jon Smuts and fast bowler Lutho Sipamla, while England picked batsman Tom Banton and leg-spinner Matt Parkinson.
"The wicket looks good but it could be a bit slow," said De Kock. "It might speed up under lights and come on to the bat a bit better."
Morgan said he had been in two minds about batting or bowling on a ground where results have favoured the side batting first.
"We probably would have bowled but it was 50-50," he said.
England all-rounder Chris Woakes was playing in his 100th one-day international.
Quinton de Kock (captain, wkt), Reeza Hendricks, Temba Bavuma, Rassie van der Dussen, Jon-Jon Smuts, David Miller, Andile Phehlukwayo, Beuran Hendricks, Lungi Ngidi, Lutho Sipamla, Tabraiz Shamsi
Eoin Morgan (captain), Jason Roy, Jonny Bairstow (wkt), Joe Root, Joe Denly, Tom Banton, Sam Curran, Chris Woakes, Tom Curran, Chris Jordan, Matt Parkinson
Umpires: Gregory Brathwaite (WIS), Shaun George (RSA)
TV umpire: Aleem Dar (PAK)
Match referee: David Boon (AUS)