South Africa may have already engineered an unassailable 2-0 lead in their Test series against Pakistan, but Hashim Amla insists that doesn't mean they'll be relaxed heading into Friday's third and final Test after being challenged by their visitors last time out.

The Proteas wrapped up the series thanks to a three-wicket win in the second Test at Newlands last week, in an encounter in which they were pushed by a stubborn Pakistani outfit.

Graeme Smith's men have enjoyed great success in the Test arena thus far this season, beating Australia in their own backyard before demolishing New Zealand at home and now accounting for Pakistan on home soil.

With this in mind, Amla admits that the Cape Town Test was the most challenging they have encountered since returning to South Africa.

"This Test took us to our limits in certain respects," he explained. "We were under pressure in our first innings and then chasing 190 in the second innings was never going to be an easy task, but the way the bowlers bowled in the third innings really set things up for us."

Saeed Ajmal was the most successful of the Pakistani bowlers, picking up six wickets in the first innings and four in the second, a haul that included Amla's scalp - twice.

Amla was full of praise for the spinner but reveals that the South African batsmen are slowly starting to work him out, with the number three having notched up an invaluable second innings fifty before edging one back onto his stumps.

"First and foremost he bowled really well," Amla said of Ajmal. "For any bowler to pick up a ten-for is a great effort.

"I think as the game went on most of us understood his bowling a bit more. We haven't faced him lot. Fortunately we weren't chasing a huge total so from a personal point of view I was able to hang in there long enough to get the guys close enough."

Fast bowler Mohammad Irfan impressed on debut, and much is expected of the 7 ft 1 in bowler heading to what is expected to be a pace-friendly wicket at Centurion.

"Irfan bowled quite well at Newlands and it's not often you face someone so tall. He got a lot of bounce but, fortunately for us, we face Morne [Morkel] regularly in the nets, so we have an inkling of what he's like," explained Amla.

"Obviously if he had played at the Wanderers, where there was a lot of bounce, we would be have a better idea if he is going to be effective. But let's wait and see what Centurion is like, if it has a bit of pace and bounce, then all the seamers will come into play more."

While the series may be in the bag and the top Test ranking secured, the Proteas will not adjusted their mindset heading into Friday's match.

"A lot of us in the top order have got in, but haven't made massive contributions, so we're hungry to do that," he explained.

"The bowlers have enjoyed their wickets and will want to keep on in that vein, so there is a lot to play for still.

"This country is a very proud nation so we have a duty to uphold in that regard."