Brisbane Heat 117 for 6 (Neser 48*, Brown 20, Naveed 2-28) beat Sydney Sixers 116 for 9 (Hughes 23, Patterson 19, Kuhnemann 3-17, Johnson 3-28) by four wickets
Michael Neser produced a match-winning knock under pressure on a slow SCG surface as new-look Brisbane Heat qualified for the BBL final after producing a stirring upset victory over Sydney Sixers.
Powerhouse Sixers were strong favourites, having won their last eight matches on their home ground coupled with Heat losing batters Usman Khawaja, Marnus Labuschagne and Matthew Renshaw to Australia's tour of India.
But after electing to bat, the Steve Smith-less Sixers were strangled by an accurate Heat attack backed up by sharp fielding.
The lowly total appeared enough until Neser hit a BBL career-best 48 not out off 32 balls to mow down the target with 10 balls to spare as Heat's remarkable rejuvenation continued.
Having won seven of their last eight games, including previous road finals against Sydney Thunder and Melbourne Renegades, Heat are on the brink of an unlikely second BBL title.
Their only grand final appearance was in 2012-13, when Heat beat Perth Scorchers who they will meet on Saturday at Optus Stadium.
Neser steps up for shorthanded Heat batting order
Having studied Sixers' innings, Heat wisely decided to go for broke against the new ball, with opener Josh Brown hitting two sixes off Steve O'Keefe.
Playing his first match of the season, filling the shoes of Khawaja, Sam Heazlett wasn't fazed and smashed a boundary off his second delivery before hitting a six over deep square leg off seamer Sean Abbott.
But disaster struck on the next delivery when Heazlett was run out after running on an overthrow to spark a collapse for Heat.
Much like Sixers' batters, Heat struggled to score and slumped to 56 for 5 before Neser and recalled Max Bryant rallied with a 30-run partnership.
Bryant threw his wicket away in the power surge, but Neser continued to hold his nerve and blasted four consecutive boundaries off seamer Hayden Kerr in the 16th over to spectacularly swing the match.
He had some luck along the way, but Neser sealed an upset for the ages with a boundary to trigger celebrations for Heat.
Sad end for Dan Christian
Defending just 117, Sixers remained confident, given their wealth of experience and domination over many years at their favoured SCG.
Their confidence was justified when O'Keefe found a leading edge to remove Heat skipper Jimmy Perison which was followed by a spectacular return catch from spinner Izharulhaq Naveed to dismiss Sam Hain and put Sixers in the box seat.
But Sixers could do little against the hot hand of Neser as their hopes of a fourth straight BBL grand final appearance quickly evaporated.
The defeat ended the career of allrounder Dan Christian, who won three BBL titles for different franchises.
Spin duo strangle Sixers
Even though they were shorthanded with the bat, Heat still boasted a strong pace attack led by Neser and breakout quick Spencer Johnson.
But with spin set to be a key on this surface, the absence of legspinner Mitchell Swepson, who is also part of Australia's tour of India, loomed large for Heat.
Their fears were allayed by frontline spinner Matthew Kuhnemann and part-timer Nathan McSweeney tying down Sixers after the powerplay.
McSweeney, who had only bowled three overs in seven previous BBL matches, set the tone with his accurate offspinners frustrating Sixers' batters.
Left-armer Kuhnemann made an immediate impact with the wicket of out-of-form opener Josh Philippe then had skipper Moises Henriques plumb lbw with a quicker delivery.
He finished a terrific spell, marked by a slew of deliveries that skidded off the surface, by removing Daniel Hughes, while McSweeney claimed his first BBL wicket when he dismissed Jordan Silk.
The quicks did the rest in the backend as Johnson continued a fine debut season with his first three-wicket haul in the BBL.
Smith-less Sixers fail to cope with conditions
Without Smith, Sixers were forced into a reshuffle, with veteran Hughes recalled having played just three games this season.
But Kurtis Patterson returned to the top of the order after batting at No.3 when Smith was in the line-up and he started fluently with a superb drive through the covers off Neser.
Patterson, who this season had been unable to match the heights of his BBL breakout with Perth Scorchers last year, got off to a flyer but again couldn't go on as he miscued a short delivery from Johnson and was caught at deep square leg by Kuhnemann.
Batting at No.3, Hughes' experience was needed with Sixers struggling in challenging batting conditions. With wickets falling around him, Hughes dug deep but hopes of a dream return ended when he was bowled by Kuhnemann.
His 23 off 24 proved the top score for Sixers, who just couldn't get going.
It was left to allrounder Hayden Kerr in the death to try to lift Sixers to a competitive total. But he couldn't replicate his match-winning unbeaten 98 in the corresponding match last season, as Sixers fell short of a desired total.