Analyst Nathan Leamon placed a series of signs in front of him, containing numbers and letters, to advise Morgan, prompting criticism from the likes of Michael Vaughan.
"There’s always been constant verbal or physical communication from the changing room to us on field to help improve my decisions as captain and Jos [Buttler] as vice-captain,” said Morgan. “It’s something we’ve used a lot pre-game and are now experimenting with during the game in order to see if we can improve our performance.
“It’s 100 per cent in the spirit of the game. There’s nothing untoward about it. It’s about maximising things we are taking in and measuring it against coaches recommendations and the data of what’s going on.
"We’re definitely going to continue with it. Enough sample size to see if it improves our decision-making on the field or our performance, or it might tell us more about how we understand information we are taking into the game."
Morgan had short shrift for the criticism he had received, saying it was in the pursuit of team improvement.
“I think captains are different,” he said. “You get captains that enjoy the title and the power and the accolades that go with it. Then you have other captains that continue to be pushed and want to learn for the benefit of the team.
"For me this is a system we want to use to try and help myself and the other leaders within the side almost take a little bit of the emotion and the feel of the decision-making on the field and compare it to the hard data that is continuing to feed information to us on the field.
“For me, captaincy has and hasn’t changed. As leaders within a group you continue to change with either trends of younger players coming through, trends of the game and what’s needed at that moment in time.”
Morgan said he has made no decisions about the balance of England’s side, which is weakened by the resting of Ben Stokes, Sam Curran and Jofra Archer. There should be opportunities in the series for the likes of Sam Billings, Moeen Ali and Mark Wood to press their case for inclusion in England’s T20 side as next year’s World Cup in India approaches.
Morgan says that ODI cricket is now the proving ground - an inversion of the situation in the lead-up to last year’s 50-over World Cup.
“I think given the strength of the T20 squad, and will do for one or two more series before the World Cup, there will be limited opportunity in T20 games,” he said. “In order to get a run it would be nice to see guys put their hand up in 50-over games.”
South Africa are also weakened by the absence of Faf du Plessis for rest and Kagiso Rabada through injury.