It's been some week for Spencer Johnson

It has been some week for Spencer Johnson. On Sunday, he was playing in the final of the Global T20 Canada. On Monday, he was called up by Australia for their T20I series in South Africa later this month. And on Wednesday night, he finished his debut for Oval Invincibles in the Hundred with ludicrous figures of 3 for 1 from 20 balls.

At the age of 27, Johnson had never set foot in the UK until Monday morning, when his flight landed. He trained once with the Invincibles, a brief indoor session on Tuesday morning, before taking the field against Manchester Originals, taking the new ball with Phil Salt and Jos Buttler at the other end. "It was a little bit intimidating," Johnson said with a smile.

Invincibles picked him as a last-minute replacement when Ihsanullah, the Pakistani tearaway, suffered an elbow injury shortly before he was due to travel to the UK. He arrived late because of his commitments in Canada, which came straight after a stint with the Los Angeles Knight Riders in the inaugural Major League Cricket season.

Tom Moody, Invincibles' coach, gave Johnson some simple advice about bowling at The Oval before he arrived. "Moods said when he rang and asked if I was keen to come over, 'You're going to love it here - it's similar to the Gabba,'" Johnson recalled. That was the venue where he became a breakout star of last year's Big Bash, bowling with good pace for Brisbane Heat.

His gameplan was simple enough: to hammer away at a hard length, using the pace and bounce that tends to be evident at The Oval. "That six-to-seven-metre length is what I bowl. That's my natural length, so I didn't have to think too much," he said. "It was cool!"

Johnson's first five balls cost one leg bye, and included one prolonged appeal for lbw against Buttler. His second set of five included the solitary run he conceded off the bat - Buttler tucked him out to deep square leg - and included two plays-and-misses from Salt, who looked totally out of sorts in his 11-ball 2.

By the time he returned, the game was over as a contest: Originals were 58 for 6 after 60 balls, in theoretical pursuit of 187. But his final 10 balls, delivered in a row from the Pavilion End, were still remarkable: Usama Mir spooned to mid-off, while Tom Hartley and Josh Little were done for pace and had their stumps flattened.

He broke various records: most obviously the cheapest spell in the Hundred's brief history, but also the fifth-most economical spell in T20 cricket worldwide and the second-most in any major league. As Heinrich Klaasen collected the match award for his 27-ball 60, he said: "Credit must go to Spence - I don't know why he's not standing here."

Johnson is still jet-lagged after his flight and struggled for words in a post-match interview with Sky Sports. "It's an absolute blur at the minute," he said. "To be here in front of these awesome fans, playing at The Oval, it's awesome. I'm pinching myself, really."

His pace - in combination with Gus Atkinson, who was clocked at 95mph on Wednesday night - along with the trickery of the Curran brothers, and the spin of Sunil Narine and Nathan Sowter, makes the Invincibles attack one of the strongest in the competition, and they are top of the table three games into the season.

If they do reach the knockout stages for the first time, they will have to do without Johnson, given his Australia call-up. "I didn't officially get told until the back end of last week. It's obviously pretty cool to, hopefully, be debuting for my country. It's a little bit tough to take in."

He has spent much of his adult life battling injuries, explaining why as a 90mph, left-arm fast bowler, he has barely played any professional cricket in his career. But nobody who saw him play on Invincibles debut would be surprised by Australia's interest in him.

"From where I was to now, I've just taken everything in my stride," Johnson said. "I keep saying the term 'ride the wave', and that's what I try to do." It is working well enough for him so far.