The Swans produced a masterclass in composure and effectiveness to defeat cross-town rivals Greater Western Sydney in a spirited derby at the Sydney Cricket Ground on Saturday night.

The Giants dominated the start of each quarter and won more possession, both contested and overall, across the match but the Swans' experience and class saw them prevail to secure a 21-point win.

Lance Franklin kicked 5.5 in a dynamic effort and linked well with young gun Isaac Heeney, who again backed up the experts' high expectations, cracking four goals in an eye-catching performance in front of 31,966 fans. Heeney was subbed out late in the match as a precaution after colliding with a goal post, but was fine afterwards.

"I don't think it's sunk in yet that I am playing with such a high profile player," Heeney said of his partnership with Franklin. "Bud kicked 5.5 today and I kicked four, which was pretty good for me. Playing with that quality all around is insane."

The Giants statistically kept pace with the Swans for most of the match. However, their poor execution in front of goal cost them. The sides had 16 scoring shots each at half time but the Giants trailed by 35 points. By the end, the Giants had just one shot fewer but were still well behind.

By contrast Franklin and Heeney took more of a toll, feeding off the work of midfielders Dan Hannebery who had 35 touches, Jarrad McVeigh who grabbed 28 and made six tackles and Kieren Jack who had 24 and three.

"There was a couple of stages throughout the game where [the Giants] kicked three or four in a row. We needed to make sure we steadied the ship and we did," Swans coach John Longmire said.

"To the senior players' credit, in particular, they were able to do that - all the players were able to do that - steady the ship and give us another buffer when they were starting to come at us.

"I was pleased with the players being able to respond the way they did. [The Giants] are a good team, a good team with talent all over the ground and experienced players."

Longmire's counterpart Leon Cameron said his side paid for not taking their chances.

"Bad kicking for goal is bad footy at times," Cameron said.

"We've got to make sure that our goalkicking is better and finishes off the hard work that the lads are doing up the ground.

"If you make one little mistake, whether it's a shot on goal or a missed handball or a turnover, [the Swans] punish you. And they clearly punished us when we did make those mistakes.

"I thought our boys hung in there and their effort was good. It's just that polish at the end where you're kicking a goal or making a decision inside 50."

In the first term, the Giants yielded just 12 points from seven scoring shots. Jeremy Cameron scored their solitary major, but missed three other opportunities.

The Giants began the second term with polish but again had little to show. Following Lachie Whitfield's opening goal the Swans hit back with both barrels to open up comfortable half time lead.

In the third term the Giants again burst out of the blocks, with Cam McCarthy scoring twice and Ryan Griffen another, all within the first six minutes. Rhys Palmer scored a fourth to reduce the gap to 14 points before the Swans responded with four of their own. And, in keeping with the pattern, the Giants got away in the final quarter before Sydney again took control until they had done enough.

For GWS, Whitfield led the possessions with 37 and Devon Smith had 33, while Stephen Coniglio made 10 tackles. Palmer finished with three goals and McCarthy and Cameron scored two each. Ruckman Shane Mumford was reported for rough conduct after an incident involving Jeremy Laidler in the second quarter.

DISPOSALS

Sydney: Hannebery 34, McVeigh 28, K.Jack 24, Lloyd 24, Kennedy 24

GWS: Whitfield 38, Smith 33, Treloar 28, Greene 27, Scully 27