Essendon coach James Hird has paid tribute to evergreen defender Dustin Fletcher after the Bombers’ thrilling win over St Kilda at Etihad Stadium on Sunday. 

On Thursday Fletcher will celebrate his 40th birthday, and the Dons’ stalwart has shown no signs of slowing down in his 23rd AFL season.

The key defender kept the Bombers in the game on Sunday, with a brilliant first half of football that included a desperate goalline smother in the second term to stop a certain Tim Membrey goal.

At the main break Fletcher had 15 disposals, two inside 50s, five defensive rebounds and was the Bombers' No.1 ranked player for metres gained.

An early hit to the mouth in the opening minutes of the third term resulted in Fletcher being subbed out under the concussion rule for 20 minutes.

He returned to the field just before three-quarter time, and while his impact was limited in the final term, it didn't stop Hird from singing his praises after the game.

"I thought he was excellent," Hird said after Essendon's two-point win.

"He's started the year really well, he's only missed one game so he's getting closer to that 400 mark.

"Fletcher is an inspiration to all of us. He's remarkable really because he's continuing to play AFL football at the age of 40 and there's not many people capable of doing that.”

Hird said he was "relieved" to steal victory against the Saints on Sunday.

The Bombers, who now sit 3-2 for the season, face an undefeated Fremantle side next Saturday night at Domain Stadium. 

Hird said the Bombers needed to improve on Sunday's performance if they were going to challenge the in-form Dockers.

“They're obviously in fantastic form and if we don't (get) the contest part of our game right then we'll struggle against the best teams,” he said.

“We've played Sydney, Hawthorn and Collingwood, who are all in that top four area, and obviously competed well against two of those three teams, so not all is lost.”