The Sixers survived a drenching Canberra thunderstorm to outclass their Sydney rivals by five wickets and surge clear atop the Big Bash standings on Wednesday night.
Wicketkeeper Josh Philippe (64 off 36) did the bulk of the damage in chasing the Thunder's rain-revised 129, returning to Manuka Oval where two years prior he announced himself to the capital with a stylish half century against South Africa for the Prime Minister's XI.
Almost picking up where he left off two summers ago, Philippe carted the hapless Thunder bowling attack to all corners of the ground, taking 23 off one Jono Cook over before he was dismissed late on by Daniel Sams with the scores level.
Late support from the typically destructive Dan Christian whose unbeaten 15 off five balls included two brutally bludgeoned sixes.
"The plan was just to assess the wicket early and go from there," Philippe said.
"After a few balls I felt like it was coming on pretty nice so I decided to take it on and chase that bonus point total.
"I was there for the whole innings and would've loved to have been there to finish it off but that's cricket. No matter how many runs you're on, when you get out it's always disappointing."
The win accelerated the Sixers' progress atop the Big Bash standings and put them more than a game clear of their second-placed Sydney rivals.
There are seemingly no weak spots in this Sixers side and with Test stars Mitchell Starc and Nathan Lyon potential additions for the finals, alongside regular captain Moises Henriques and star quick Sean Abbott, they look perfectly placed to defend their BBL crown.
At one stage on Wednesday it looked like the points would be shared as torrential rain swept across Manuka moments after the Thunder walked off having compiled 6-166.
Half centuries to Alex Hales and Daniel Sams bookended the innings, which crumbled in the middle order before the latter made the total respectable.
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Ground staff rushed onto the field at the innings break and covered the wicket just seconds before sheeting rain left Canberra cricket fans, witnessing the first ever Sydney derby in the capital, scurrying for cover.
The Sixers were already safely nestled in the changerooms, no doubt patting veteran Stephen O'Keefe on the back after his 3-15 from four overs wrested momentum to the eastern fringe of the Harbour City.
Hales (54 off 33) threatened to post a huge score before O'Keefe had him caught by Jordan Silk in the deep. He also claimed the wickets of Sam Billings and Alex Ross.
"I thought we put a good score on the board with a slowish wicket, it was taking some turn, we had a score that we could defend for sure," Thunder captain Callum Ferguson said.
"We probably looked like we were going to get a bigger score, we lost our two set batsmen just before the 10th over which is unusual for us.
I thought the way Samsy batted got us to a total that I thought was very defendable. We weren't quite good enough.
"We probably didn't execute our gameplan as well as we can, some areas to improve on that's for sure but we fought back really well and took the game deep."
O'Keefe and the Sixers are now on 29 points and will all but wrap up a crucial top-two finish with a win over Hobart in Canberra on Saturday.
Meanwhile, the Thunder have now slumped to a third loss in four matches and their early season charge looks to have lost significant steam ahead of a crunch clash with Hobart on Monday.