Needing two runs off the final ball of their women's Big Bash innings to force super over, the Sixers' Sarah Aley managed only a single when her shot went straight to short fine leg.

Melbourne started celebrating as soon as wicketkeeper Emma Inglis caught the underarm return from the field, but she dropped the ball and joined her jubilant teammates with their backs to the wicket, allowing Aley to take off from the non-striker's end and dive safely into her ground to secure a second run.

Renegades players immediately confronted the umpires arguing the ball was dead, but the second run was allowed to stand.

"I think it's a pretty good learning curve for us to be honest, we sort of learned in the moment what it means for the ball to be dead," Renegades captain Amy Satterthwaite said. "The umpires are saying that it's not over until the batters stop running, so in that case we have to hold the ball. So we've learned the hard way I guess, and fortunately we still got over the line in the super over.

"In the girls' minds they've thought that that's dead. Often when the 'keeper catches it that's been the case. But she threw it up in the air and so then the batters took off for another run."

The laws of cricket state the ball becomes dead when "It is finally settled in the hands of the wicket-keeper or of the bowler" and that "The ball shall be considered to be dead when it is clear to the bowler's end umpire that the fielding side and both batsmen at the wicket have ceased to regard it as in play".

They also state "Whether the ball is finally settled or not is a matter for the umpire alone to decide".

Aley was alert to the situation and took full advantage.

"From my point of view it was still in play because the stumps hadn't been broken or anything like that," Aley said.

"I just went for it and I ran and I kind of knew that as long as we got two runs that took us to a super over and we were still in the game."

It was all in vain for the Sixers, who only managed to score 2-8 from their super over, which allowed Melbourne's Jess Duffin to hit the winning run required on the final ball of the match.

Sydney had been cruising at 2-81 chasing Melbourne's modest 7-120 before Maitlin Brown took a superb diving catch at long off to dismiss Ellyse Perry for 37.

The Sixers' innings collapsed before ending in farce on the final ball, as the visitors missed the chance to go a game clear at the top of the table.

"We were just talking about it then, at 4-90 and 30 off 36 it's a game that we really should've won," Aley said.

"We put ourselves under pressure a fair bit there with quite a few dot balls and losing a couple of wickets at key points, something that we'll go away and we'll work on and we'll think about long and hard and make sure that if we're in that situation again to make sure we play it the way we know that we can play it. Next time we'll get that game with two overs to spare."