Australia fast bowling legend Dennis Lillee has backed Mitchell Johnson to feature in the Ashes against England next year, saying the veteran paceman has adapted his game to account for his age.

Johnson is no longer the super-fast bowler of five years ago, but under Lillee's mentorship he has added variety to his armoury. Lillee has been impressed with his protege's development, and feels the Three Lions will have a tough time against him.

Johnson has to compete for a place with Peter Siddle, James Pattinson, Micthell Starc, Pat Cummins, Ben Hilfenhaus and now John Hastings, but Lillee thinks Johnson has an advantage thanks to his experience.

Lillee told ABC Radio of the 31-year-old: "He's finally decided that he's going to that second phase as a fast bowler and that's one that he's not going to blast guys out.

"He's going to bowl some variety, he's going to concentrate on a really good line and length and sort of play that support role a bit more.

"I thought the way he's bowled so far in (the Sheffield) Shield and the way he bowled in this (third) Test is an indication that he's on song with all that, and he's happy in his mind about that.

"You haven't seen any of the balls going wide of off stump, wide of leg stump. There is some technical work we've done with him but it's also about him being convinced he's going to that second phase."

Johnson took two wickets in his 17 overs in South Africa's first innings, helping to reduce the Proteas to 225 all out.