Steyn tore through the Australian batting on Sunday to drive his side to a 231-run second-test win in Port Elizabeth that levelled the series at 1-1. (Agencies)
But on a Newlands wicket that is likely to be quicker with greater bounce, he believes Morkel may well be the most effective of the South African pace attack.
"I thought Morne bowled extremely well on a flat wicket in Port Elizabeth and did the business. It was a different Morne from what we have seen," Steyn told reporters on Thursday.
"He was bowling up at 150 kilometres per hour, bouncing the batsmen and when you are in the field watching that, it lifts everybody. Morne was the guy who really started things off for us in that first innings and he didn't get the credit he deserved."
Steyn has been the spearhead of the South African attack during their rise to number one in test cricket. Often regarded as angry and aggressive, he says he is misunderstood.
"It's focused aggression, I have to be in that state of mind to put in those kinds of spells," Steyn says.
"If I am thinking about teddy bears when I come in to bowl I'll serve up half-volleys for the batsmen to smash.
"I feel like I have to be ready for a fight. It's a bit embarrassing when I watch it on the news afterwards, but it helps my country get results and that is the most important thing."
Steyn would not be drawn into the furore started by Australia opener David Warner, who said his team believed AB de Villiers was using his wicketkeeper gloves to tamper with the ball, helping South Africa's fast bowlers to find reverse swing.
"I haven't followed the story much, to be honest, but a lot of us play cricket in India where you learn to bowl with different skills. It would be a lot better if people were rather talking about how well you execute your skills."
The 30-year-old is looking forward to returning to Newlands, where South Africa have lost one of their last 16 tests and where many of the team, Steyn included, play their provincial cricket.
Steyn tore through the Australian batting on Sunday to drive his side to a 231-run second-test win in Port Elizabeth that levelled the series at 1-1.