Mitchell Johnson has mellowed and is unmoustachioed these days, but the menace remains. That much was clear at the Waca as he blasted Perth Scorchers into their fifth BBL final in the competition's six seasons. After claiming an astonishing 3 for 3 in his four-over new-ball spell, there was no way back for Melbourne Stars.

Johnson is no Samson; he awoke on Tuesday morning with facial hair, but lopped it off. "I had a beard thing on this morning but decided it was too gross, it was really bad and so I trimmed it down. Maybe I got through the breeze a bit quicker."

Johnson cited the absent moustache as a reason he is friendlier these days; of Kevin Pietersen, who arrived at the crease for the second ball of the match, he said: "I was probably too friendly to him."

He also believes, contrary to what his bowling figures might claim, that a lot of his aura has vanished since the end of his international career. "I get in the moment and enjoy it, but I don't feel I'm as devastating as I was." And he simply does not feel as quick either. "It didn't feel like 146 [kph]," he scoffed, when told what he had clocked on the speed-gun.

"I have moments where I get really excited but I don't think it will ever be the same as what it was a few years ago," he said. "I said that at the start of the tournament - I won't be the same Mitchell Johnson that I was three years ago or 10 years ago. It's today and this is how I am. I felt a little slower than normal in this game, but that suited the wicket perhaps. I celebrate like I was 20, so that's a good thing. I cherish the game and love it."

Today's performance must have been one of those "moments" that Johnson refers to. Rob Quiney and Luke Wright were dismissed in the first over, a maiden, while KP went in his third. He did not concede a run off the bat until his 18th ball. He had looked menacing against Hobart Hurricanes on Saturday too, hurrying out key men Tim Paine and Ben McDermott. Perhaps it is because he is relaxed these days, and a bit more philosophical too.

"I still want to win and have that hunger, but I'm probably stressing about the game a little less than I was," he said. "Coming into this I was laid back, excited but normally I'd be stressing out and thinking about what I need to go, going through all the batters. I haven't looked at all the batters before this game and the last game. The hunger is still there.

"It doesn't matter how you get them in this game," he said of the Quiney wicket, caught at fine leg off the opening delivery of the match. "As bowlers, you go for big sixes and get little inside-edges, so it was nice to have luck go my way first ball of the over. And it really just set the tone. That's what I have enjoyed about getting the new ball - there is that little extra pressure, I guess, as an opening bowler, you want to get quick wickets up front, but to do it like that was very enjoyable.

"I feel in good rhythm. My cues and everything I used to think about feel good, and that has taken a couple of games to get there. Hopefully I can stay at that pace. If I do, it's tough to get away, but I'd rather bowl fast than 125 [kph]. I might as well give up if I'm down there. Not many teams would sign me up bowling 125."

One team he will not be playing for again is Australia. Many wise old heads have been touted for a run against Sri Lanka next month, including Quiney and Michael Klinger, Johnson's Scorchers team-mate. Johnson, however, will not be joining them. "It would be nice but I don't think I want to play," he said. "I don't think it would be as enjoyable for me. I had my moment in the sun, and these young guys are playing better cricket than I am, I just don't think it would work. There's too much stress at the top level."

He did, however, come close to signing for the Pakistan Super League and is looking at IPL deals now. "The fresher I stay the better. There are a few little tournaments later in the year, not so serious, that are around."

Could England's NatWest T20 Blast be counted about those 'not-so-serious'? Tim Bresnan and Ian Bell, team-mates at Scorchers, have certainly been in his ear to play next season. "It's been mentioned and it could be an option," he said.

And, after that, he will be back with the Scorchers, although not at the Waca, which is making way for a new purpose-built stadium next season. "I will miss playing here," he reflected. It is a ground indelibly linked to Johnson at his most fearsome; how nice it would be to see him fire there once more time.

Will Macpherson writes on cricket for the Guardian, ESPNcricinfo and All Out Cricket. @willis_macp