It was the catch of the summer. Sir Viv Richards reckons it was one of the best he's ever seen – and you'd suspect he's seen a few.

And it was a special moment that changed a stunning game in favour of the Sydney Sixers, who put a massive dent in the finals hopes of defending Big Bash champions Brisbane Heat with a breath-taking triumph at the Gabba.

With a sub-par 8-140 on the board, the Sixers were always going to face an uphill battle to defend their total on a quality Brisbane pitch that offered the batters no excuses.

Some more big-hitting from the in-form Chris Lynn (34 off 21) had the home side in a solid position at 4-96 with more than enough overs in hand. It looked as if they would roll over the line.

Craig Kieswetter was finding his range and looked the matchwinner for Brisbane, until Jordan Silk came up with one of the great grabs to spin the contest on its head.

Brett Lee fired down a 140kmh firebolt that Kieswetter crunched, middling it past mid-on and already adding the extra four runs to his tally. It was a boundary for all money.

But Silk circled, launched into a full-length dive and popped up with the ball fused to his left hand. Ricky Ponting rates him the best fielder in the country and on that evidence, it would be impossible to argue.

“I think it's a fluke. It was nice that it stuck,” Silk said.

Few who witnessed it will forget the catch but the drama of the contest was almost as memorable. Brisbane looked gone when Silk had Kieswetter on his way for 38 but Ben Cutting almost pulled the match from the fire with some final-over heroics.

The big all-rounder should have been sent in earlier but had just six balls to conjure the 20 runs required for victory. Chris Sabburg (19 not out) never got going so it was left to Cutting to take on Josh Hazlewood.

His first ball was too good, a yorker outside off. But he sent Hazlewood into the stands soon after, leaving the Heat needing a six off the final ball for victory, or a four to prompt a cut-throat super over.

He clubbed it and it looked on its way before it dropped short and was nabbed on the boundary by Sixers skipper Moises Henriques.

Brisbane fell five short of victory, ending the night at 7-136. The Sixers live to fight another day and Silk is about to become a YouTube sensation.

Earlier, Michael Lumb set up the Sixers with a cavalier 56 off 42 balls, while Cameron Gannon (4-24) was the pick of the Brisbane bowlers.