Australia fast bowling coach Craig McDermott was surprised by Mitchell Johnson's retirement but believes he has seen a changing of the guard.
After 73 Tests and 153 one-day internationals for Australia, Johnson announced the second Test against New Zealand would be his last game for his country.
The 34-year-old, who has taken 311 Test wickets, had spoken about potential retirement in the lead up to the clash at the WACA.
McDermott said he did not see Johnson's decision coming, but backed the left-armer.
"Obviously he wouldn't be happy with the way he bowled in Brisbane and here as well," he said on Tuesday.
"It's obviously been on Mitchell's mind for a while and you guys have been talking about it for a while so he's finally made the decision.
"He's happy with that and that's really all that matters when you retire - that you're happy with your decision for both you and your family and he's obviously made that decision and good luck to him."
McDermott named the likes of Peter Siddle, 12th man in the first two Tests, James Pattinson and Nathan Coulter-Nile as potential replacements.
But McDermott said the man who had replaced Johnson was already playing for Australia - Mitchell Starc.
"I think, if anything, we saw the changing of the guard here two days ago, with Mitchell Starc bowling consistently 150-odd kilometres per hour," he said.
"Sitting back and watching that, I thought that was like the changing of the guard for me and hopefully Mitchell Starc can have as illustrious a career as Mitchell Johnson has."