Sydney' thrilling three-point win over Essendon on Thursday has come with some costly collateral as gun forward Isaac Heeney faces a spell on the sidelines after suffering a broken hand.

Heeney is likely to miss close to a month of football after sustaining the injury to his right-hand in the second-quarter of the Swans' 11.17 (83) to 12.8 (80) victory over the Bombers at the SCG.

The 24-year-old was a key contributor in the first-half of the game, amassing nine disposals and six marks before having his night ended early.

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Heeney played the opening six games of the 2020 season prior to having his campaign plagued with an ankle injury, where he was ruled out for the remainder of the year.

Speaking after the Round 4 win, Swans coach John Longmire expressed his sympathy for the Sydney star.

โ€œItโ€™s just terrible luck for him. Heโ€™s one of our best preparers; he trains so hard, heโ€™s worked so hard to come back from his ankle (injury) and heโ€™s got a crack in his hand,โ€ Longmire said, perย The Herald Sun.ย 

โ€œ(Heโ€™ll miss) three, four weeks, I guess, depending on what happens โ€ฆ Iโ€™m not sure on what the official diagnosis is, but what Isaac is, is a really positive person.

โ€œHeโ€™ll get over that disappointment tonight and get to work and get himself right, but heโ€™s been in great form for us this year and heโ€™s a really important forward threat.โ€

The Swans now sit 4-0 after the opening month of the season following wins against Brisbane, Adelaide, Richmond and Essendon.

The last time the Bloods went undefeated after four games came in 2012, the year of their most recent premiership.