Mortlock, still pained by his side's 12-10 quarter-final loss to England almost a fortnight ago, said the defending champions had played intelligently by adopting a forwards-orientated game dominated by stout defence.
However, he warned England's gameplan must change if they are to become the first nation to win back-to-back tournaments by beating South Africa in the final in Paris on Saturday.
"England have played smart and played to their strengths," Mortlock said.
"Their tactics have been pretty consistent the last three times and I wouldn't think they'd change too much.
"They've had a lot of knockers, especially during this World Cup operation, and I think they've proved them all wrong by continuing to win.
"Try-scoring opportunities have been hard to come by and decisions have had a big impact on the results, so they've played smart and that's why they're in the GF (grand final)."
But Mortlock warned England that their simple but effective gameplan will not be enough to knock over the Springboks.
"South Africa have the ability to overcome those tactics," he said.
"I can't go past South Africa. They've got a quality team, playing some good footy.
"It will be very tight but I'd say they'll come out the winner."
Meanwhile, Mortlock has rubbished reports he will miss next year's Super 14 season, declaring he will be back by April after undergoing shoulder surgery.
The Brumbies centre is due to undergo a reconstruction - his third such operation - after carrying the injury throughout Australia's failed World Cup campaign.
It was feared the 30-year-old centre may be out of action until next year's international season, but those doubts were allayed on Wednesday.
"The report was that I'd be out for the whole Super 14 but hopefully it isn't on the money," Mortlock said.
"We're looking at a six-month rehab so I should be back in an April window somewhere.
"I should be back mid-way through the Super 14 towards the business end of the season.
"It's not ideal but I did know about it for a while and worse things can happen.
"Hopefully I get through the operation and everything goes smoothly and then I'll rip into rehab."