Wednesday's thumping win over the Sydney Thunder shot O'Keefe's side six points clear atop the BBL standings, and they took a gigantic stride towards top-two qualification and the defence of the title they won last season in the process.

But the 36-year-old feels admitting five teams into the post-season is overkill, especially after recent expansion to the competition two years ago which fleshed out the regular season to 14 matches per team.

Big Bash organisers introduced a finals 'eliminator' last season, which pitted the fifth-placed team against fourth. That happened to be the Thunder, and they advanced all the way to the preliminary final before losing to the Melbourne Stars - who were then beaten by the Sixers.

"It's just done so they produce more games of cricket," O'Keefe said.

"You can still play a four game finals series and give one and two the opportunity to play off against each other, the winner goes through, the loser plays the winner of three and four.

"When you play 14 games and you're giving five teams the opportunities to play in the final, it just takes away and discredits the tournament as a whole.

"If you're good enough to play in the finals and you earn that fourth position, I don't think you should be having to play off against the fifth team.

"We'll be aiming to finish in the top two and that gives you the double crack at it and I think that's the most benefit that you're going to get. There's no real value of finishing third."

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O'Keefe wound back the clock on Wednesday night, claiming a BBL career-best 3-15 from his four overs, helping reduce the Thunder to 6-166.

The Sixers made relatively comfortable work of chasing down a rain-reduced 129 for their seventh win.