Sydney Swans coach John Longmire has lauded ruck recruit Brodie Grundy as "enormous" for rising to the occasion with a starring role against his former side Melbourne at the SCG.

Grundy was unable to break into the Melbourne line-up with captain Max Gawn preferred ahead of him late last season after a much-debated move from Collingwood the previous summer.

The 29-year-old played like he had a point to prove in his Swans debut with an influential performance that helped his new side run away to a 12.14 (86) to 9.10 (64) victory on Thursday night.

"His second half was huge," Longmire said.

"He just kept going, just kept ploughing through. His second and third efforts, his work around the footy was enormous.

"I just feel really pleased for him. He's got that one out of the way and now he can settle into his season now, and he's got another big one next week against the Pies."

Grundy was traded to the Demons ahead of the 2023 season after 177 matches in 10 years at the Magpies. The 202cm ruck had an immediate response against his former teammate and finished with more disposals (22-15), clearances (9-2) and marks (4-1) than Gawn.

The Swans were able to overcome an injury-riddled midfield as they dominated the contested disposals 87-64 and beat the Demons at their own game in the second half.