England will pick their first-choice ICC World Twenty20 team for two quickfire matches against South Africa.
Eoin Morgan senses the outcome of the two matches - scheduled for Friday and Sunday - could have a significant bearing on England's campaign next month, because momentum, especially with victory over opponents they will also face in India, is critical.
"Nobody will be rested over the next two games," said the England captain.
"They are games we really want to win."
England decided not to train at Newlands on Thursday, after their warm-up victory over South Africa A in Paarl the previous evening, in which Joe Root, Ben Stokes and Moeen Ali were all rested.
All three can be expected to be back in action again, first at Newlands, and then in the second Twenty20 and England's final fixture of their tour in Johannesburg.
James Vince, Sam Billings and Chris Woakes are likely to make way.
Morgan added: "Twenty20 is very funny in that regard - when momentum is with you, it can be very kind, but also if you're struggling to gain it, it can be brutal.
"If you're trying to turn around momentum, and gain wins, it's a terrible game."
It was not a great one either for Morgan while he was making scores of just eight, two and two in his final three innings of the 3-2 one-day international series defeat to South Africa.
But he was back with a bang on Wednesday at Boland Park, with five sixes from the first 10 balls he faced and 42 runs from just 13.
"It felt great," he said. "I haven't felt out of form, just short on runs, and it was nice to come in and play with the freedom I like playing with.
"I'd like to come out and score some runs in these next two games - it might happen, it might not - but I'll stay true to what's worked for me in recent times.
"That has come with experience."