It was a dramatic semi-final night at the SCG to determine which team would host the third edition of the BBL final against the Hobart Hurricanes on Friday night, and in the end the Scorchers won on the final ball of the night to set up Friday's decider at the WACA Ground.
The Scorchers were sent in to bat first and were struggling at one point being just 2-55 from nine overs and Simmons struggling with five from 15 balls.
However, things then took a dramatic turn and the Scorchers ended up posting 5-193 with Simmons hammering a remarkable century.
It was just the second century of the Big Bash for 2013/14 with the 31-year-old Scorchers opening batsman hitting both of them after being called up from grade cricket to replace unavailable West Indies opener Dwayne Smith.
Simmons was way off the mark of matching 102 from 41 against the Adelaide Strikers at the WACA Ground early in his inning on Wednesday, but once he got going he was impossible to stop.
He ended up making 112 from 58 balls with his knock including an incredible 11 sixes.
The rain then threatened to undo all his good work though. If the game was called off, the victory would be handed to the Sixers and they would host the final on Friday but with two minutes to spare the game resumed with the Sixers set 54 from five overs.
Maddinson gave the Sixers a chance with 36 from 16 balls after being dropped when on five, but he was run out from the second last ball and Brett Lee couldn’t connect needing six of the last delivery to hand the Scorchers the win.
The result now means that the Scorchers will once again host the final on Friday night at the WACA Ground against the Hurricanes for the third straight year, and looking for a first victory after losses in 2012 to the Sydney Sixers and in 2013 to the Brisbane Heat.
Sixers captain Marcus North, in the absence of the South Africa-bound Moises Henriques, won the toss and sent the Scorchers in to bat and it looked to be paying off early on.
Both Simmons and Simon Katich struggled early getting just three off Lee's first over, only five of the second from Mitchell Starc and four from Josh Hazlewood's first to be 0-12 after three overs.
However, Katich then smashed Starc for three boundaries and a six in the fourth over as the Scorchers began to increase the scoring rate.
Katich was gone next over, though, when hitting it down the throat of Lee at third man from the bowling of Hazlewood.
He was out for 26 from 21 balls with the score 1-33 after five overs and Sam Whiteman then added just nine from 11 balls before being caught by Sean Abbott off Lee with the score 2-54 in the ninth over.
Simmons was yet to take off, but he was still at the crease despite being five from 15 balls at one stage.
He finally got a six away off the bowling of Trent Copeland in the eighth over, then another off Abbott in the 10th and then he began hitting consistently from the 12th over onwards.
He smashed Hazlewood for a four and a six in the 12th over, Ravi Bopara for another six in the 13th and then another one over the fence off the spin-bowling of his old WA mate North in the 14th.
Simmons then took an extra liking to Abbott's bowling in the 16th over hitting him for two sixes and a boundary as he went for 16 in the over and suddenly the Scorchers were 2-145 after 16 overs.
Adam Voges had been giving Simmons good support before being bowled by Starc for 31 from 24 balls, but the Simmons show was just heating up.
He hammered three sixes in the 18th over from Hazlewood to get into the 90s and then brought up his second century of the tournament with an inside-edge for four off Starc the next over.
Simmons then hammered Lee for a massive six from the first ball of the last over of the innings, and added another boundary before being run out for 112 with two balls remaining.
The Scorchers ended up making 5-193 from the 20 overs after at one stage being really struggling at 2-55 from nine overs.
Simmons was also five from 15 balls at one stage, but ended up making his last 107 from just 43 balls. His previous century at the WACA Ground against the Strikers saw him make 102 from 41 balls.
The rain in Sydney then threatened to end the game prematurely but the teams got back out onto the SCG with two minutes to go before the game was officially called off and handed to the home team.
However, they got back out with the Sixers requiring 54 from five overs with just a one-over powerplay.
The first over was bowled by Alfonso Thomas and after bowling a wide first up to back up what has been a disappointing tournament for the South African-born English-based paceman, he bowled a good first over going for just eight runs.
English opener Michael Lumb's poor knock then ended the next over when caught for one from six balls at the deep mid-wicket from the bowling of Jason Behrendorff.
Things then could have really come apart for the Sixers when Maddinson hit a sitter to substitute fielder Hilton Cartwright at deep cover two balls later, but he put it down with the Sydney opener on just five.
Bopara did fall for a first-ball duck in that same over with the Sixers 2-9 but Maddinson then started to get things moving with a boundary off the last ball from Behrendorff.
Maddinson then managed to take 13 from four balls from Brad Hogg's over to get the Sixers in with a chance at 2-30 from three overs needing a further 24 from 12 balls.
However, the fourth over proved disastrous with Abbott run out for one and Mark Cosgrove out caught behind from Pat Cummins for a duck with Maddinson stuck at the non-striker's end.
Dan Smith then pulled a boundary first ball for the Sixers before being clean bowled by Maddinson the very next ball meaning the Sixers needed 17 to win from the final over with Maddinson on strike.
Nathan Coulter-Nile bowled the last over for the Scorchers and brought about a play and miss first up, before the second ball went for just a couple.
Maddinson got the third ball away for a boundary through cover and then got under the next ball with it flying straight and also going to the fence.
That left the Sixers needing seven from the final two deliveries and Maddinson couldn’t quite connect on a pull shot, and then was run out attempting a desperate second run to get back on strike for the final delivery.
That ended Maddinson's terrific knock on 36 from 16 balls leaving Lee on strike needing to hit a six from his first and only ball to face.
Lee has hit some big sixes through his long career but he didn’t manage to get any bat on it whatsoever with the Scorchers hold on for the victory, and a third crack at the Big Bash League title.