Perth Heat have their work ahead to go into Christmas on top of the ABL, falling behind in their series against the Adelaide Giants after the opening three games.

The Giants lead the four-match series 2-1 after winning both games on Saturday night at Harley-Davidson Ballpark.

That sets up a tantalising decider on Sunday from 4pm with both teams entering on a 12-7 record meaning the winner of the game goes into Christmas on top of the southwest conference.

The top-of-the-table clash got underway on Friday night with a strong performance from the Heat.

Star pitcher Dylan Unsworth got his third win of the season as the Heat dominated for the 7-2 victory on the back of four runs in the fifth inning.

It was the cleanest hitting outing of the season too for the Heat with Jess Williams, Ulrich Bojarski, Jordan Qsar and Pete Kozma all delivering home runs in the victory that provided the perfect start to the series against the Giants.

Niko Hulsizer, Roberto Alvarez and Tim Kennelly all produced hits as well in an impressive offensive display from the home team.

But Adelaide hit back impressively in the first game on Saturday of a double-header.

The Giants made a flying start going up four runs in the opening inning with a double from Logan O'Hoppe proving the centrepiece of the scoring allowing for Aaron Whitefield and Jordan McArdle to score.

The Heat did fire back with three runs in the second on the back of consecutive home runs to Hulsizer and Bojarski. The home team scored twice more in the third highlighted by a double from Hulsizer to continue the cult hero's big evening.

That had the Heat leading 5-4 after an eventful first three innings. They wouldn’t score again, though, with Adelaide scoring a run each in the fourth and fifth which ended up being enough to give them the 6-5 win and level the series at 1-1.

In the second game on Saturday night, Adelaide built on that momentum scoring three runs across the opening two innings. That came against Heat pitcher Blake Bivens and was only on the back of three singles and a double.

They held that 3-0 lead the rest of the night to take both games on Saturday and take a 2-1 series lead on the road.

It all goes on the line now on Sunday from 4pm back at Harley-Davidson Ballpark.

A win for the Giants and they win the away series and will go clear on top spot of the conference.

A win for the Heat and they tie the series and will head into Christmas in first place.