Australian bowling coach Craig McDermott has praised his attack as the best in Test cricket.

McDermott expects no changes for the Boxing Day Test to the quartet that has bowled so well in this Ashes series.

Paceman Ryan Harris continues to nurse a sore knee, but McDermott is confident he will be right for Melbourne.

Rain forced Australia to train indoors on Monday morning.

Harris has combined superbly with fellow quicks Mitch Johnson and Peter Siddle and off-spinner Nathan Lyon to play a key role in Australia’s 3-0 Ashes series lead.

“They’ve all performed as a unit fantastically well,” McDermott said.

“We have the best attack in the world at the moment.’

McDermott said the bowlers were nursing a few aches and pains, but nothing serious.

Asked about Harris’ fitness, McDermott said: “I wouldn’t say there’s any doubt, he’s just sore.”

By contrast, the English are in disarray and staring down the barrel of a 5-0 series whitewash.

They suffered another blow on Sunday when veteran off-spinner Graeme Swann announced his shock retirement.

McDermott stuck to the Australian media message that their one concern is being ready for this Test.

“That’s their problem, I suppose (Swann retiring) – I’m more concerned about how our bowlers are preparing come Boxing Day,” he said.

Lyon has admired Swann as a fellow off-spinner and has no doubt his absence will give Australia a boost.

“It’s going to be a positive for Australia, but we still have to come out and pay respect to everyone that goes out there,” Lyon said.

“I was shocked – he’s someone I’ve looked up.

“He’s probably been the backbone of England’s attack for a while.

“I regard him as one of the best off-spinners I’ve seen … I’ve certainly learnt a few things just off watching him and talking to him.

“He’s been fantastic for England and for cricket, full stop.”