Sydney Thunder 157 for 6 (Billings 42*, J Sangha 30, Kerr 2-35) beat Sydney Sixers 151 for 7 (Silk 43*, Andrews 2-15, Agar 2-25) by four wickets

David Warner will have the chance to lead Sydney Thunder to their first BBL title in nine years, a season after they finished with the wooden spoon, after his side held their nerve in a scrappy Challenger final derby against Sydney Sixers to win by four wickets, with seven balls to spare.

The experience of Sam Billings proved vital in the outcome as he nursed Thunder to their target amid a regular loss of wickets. With another 18 runs needed off the remaining 13 balls, Billings broke the tension with a huge leg-side six off Hayden Kerr.

Thunder had been excellent in the field, with only a sixth-wicket stand of 56 from 34 balls between Jordan Silk and Ben Dwarshuis hauling Sixers as far as 151. Although Tom Andrews was their only spinner in the wickets - his brace came in the space of three balls - Thunder's spinners were otherwise again very effective. The ten overs between Andrews, Tanveer Sangha and Chris Green cost just 66 runs on a surface that offered assistance.

In reply, young English legspinner Jafer Chohan was very impressive, but Sixers did not have the volume of spin overs they were able to turn to as Thunder set up a final showdown with Hobart Hurricanes on Monday.

Jason Sangha opens up

Thunder have tried a variety of opening combinations this season, although some of it has been out of their hands due to injury to Cameron Bancroft, and a Test call-up for Sam Konstas. For the Challenger, they opted for Jason Sangha, alongside Warner. Jason Sangha was playing in just his second game of the season, and started with a bang by taking 14 runs off the first over.

Warner then scooped his first ball from Kerr for six, and Thunder were off to a flyer. But he bunted a catch to mid-on in the third over. Jason Sangha, meanwhile, had reached 30 off 19 balls at the other end, when he slog-swept Chohan to deep midwicket, as the game really started to tighten up.

A zing-bail run-out

When on 3, Thunder's Matthew Gilkes was given a life as he lofted Ben Manenti's first ball to long-off, where Lachlan Shaw, who has produced some spectacular fielding in the competition, spilled a regulation catch in front of the Thunder dugout. From there, Gilkes built steadily, including landing a huge six into the Members Stand off Mitch Perry. But Gilkes was then at the centre of a borderline third-umpire decision.

Coming back for a second run after playing towards deep third, Gilkes was beaten by a superb throw from Kerr. But Jack Edwards thought he had broken the stumps with his hands. However, after multiple replays, the third umpire Phillip Gillespie ruled that it was the ball that had fully dislodged the bail so Gilkes was ruled out for 26. The stump could be seen moving before the ball made contact, but, crucially, the zing bails had not lit up, so they had not been fully dislodged. Without zing bails, it was unlikely to have been given out.

That is when Sixers put the squeeze on. Hugh Weibgen under-edged on to the stumps against Kerr, and Thunder couldn't find the big over that would likely have killed the game off sooner. Chohan was superb, as he had been in the Qualifier final, and did not concede a boundary until the final delivery of his spell.

Thunder held the power surge back until the 18th over, and though George Garton fell swinging across the line, Billings and Nathan McAndrew finished the job with some breathing space.

Tanveer's fortune; Andrews' double

Amid the loss of Edwards and Kurtis Patterson inside the powerplay, which ended with Sixers just 23 for 2, it was a struggle for the hosts. Josh Philippe, who had been moved down to No. 3 after having not reached double figures in his last five innings, and Moises Henriques, were starting to engineer a platform when Henriques nailed a return catch to Tanveer, who dropped it, but deflected the ball on to the stumps with Philippe out of his ground.

Then Andrews, who has had a huge impact on Thunder's run to the finals, further dented Sixers' middle order with two wickets in the 13th over. Firstly, Henriques was brilliant caught at cover by Garton, diving full length to his left. Then Shaw picked out Warner on the off side, with the Thunder captain rewarded for aggressive fielding placement. Somewhat surprisingly, that was Andrews' last over of the innings.

Silk's forlorn finals

Silk was superb in Hobart on Monday, when he had nearly hauled Sixers over the line with 57. Against Sixers in the Challenger, he had to do another rebuilding job from 76 for 5. He broke the shackles with a sweep for six off Tanveer Sangha, and cleared the rope again in the power surge against Wes Agar.

The surge brought 20 runs from the two overs, before Dwarshuis was able to find his range against McAndrew in the 18th over, which cost 19 runs. It gave Sixers something to defend, although it wasn't quite enough in the end.