"I guess I've been forced to," he  said before Saturday's semi-final against the top-of-the-table Strikers in Adelaide. "When you're forced to hit 15-or-so an over you just have to bite the bullet and take the risk to clear the boundary.

"I knew it was a short boundary and it's all I targeted as our run rate crept up. I just tried to take the ball as deep as I could and while it might've scared a few people we got there in the end."

The 22-year-old, who needed an excruciating 341 balls to reach his century for Tasmania when they beat Queensland for the 2012-13 Sheffield Shield title, swung his bat and his unconquered 69 included five sixes and a four.

Adding lustre to Silk's knock was his last 43 runs were belted from 13 balls.

He punished Josh Lalor, who  started the final over with 4-6. His lofty hitting and Stephen O'Keefe's consecutive fours from the last two deliveries sent the NSW domestic record crowd of 36,487 into a frenzy when the Sixers hit the 23 runs that were required for victory.

Silk attributed his newfound ruthless approach to confidence.

"While we didn't get the win last week [against Adelaide] the way I played [hitting 67 off 34 balls]  gave me confidence I could play that role," he said.

"At the beginning of the summer I'd never have imagined [this kind of innings]. I knew batting in the middle order meant there might come the time where I could do something like that but to do it was phenomenal."

The Sixers, set 155 for victory, were on the canvas when Silk took strike and the scoreboard showed they were 6-75 with six overs remaining.

"I think spending more time in the middle has helped me," he said. "I'm getting more confidence from being there at the end in Hobart [31 runs off 23 balls] and then Brisbane [29 off 23]. I know I can compete at this level."

Adding to a memorable match was Silk's spectacular diving catch to remove debutant Chris Green.

Silk, oblivious to a teammate charging towards him, tore in from near the members' pavilion, dived full length and slid to just outside of the 30 metre circle to take a spectacular one-handed catch when the ball was millimetres from hitting the the turf.

It added even more weight to his reputation as one of the game's best fielders, as Nathan Lyon called him, following last year's screamer to dismiss Brisbane Heat's  Craig Kieswetter at the Gabba.

"I practise my catching and it was obviously different to the one I took last year," he said. "I just dived, I was lucky it stuck."

Silk believed the Sixers had the momentum to upset the Strikers in front of what he predicted would be a "bumper" crowd in Adelaide.