Newcastle's 2021 campaign ended on Sunday when they were beaten 28-20 by Parramatta in a sudden-death final in Rockhampton.

It was the second consecutive season in which the Knights have finished seventh and bowed out in week one of the play-offs, after a 46-20 trouncing at the hands of South Sydney 12 months earlier.

Sunday's result left Gardner with mixed emotions.

Disappointed as he was that Newcastle's season was over, he was nonetheless proud of their belated revival after a spate of injuries threatened to leave them languishing with the also-rans.

"Reaching the finals two seasons in a row is a great effort, given where the Knights were at when the Wests Group took them over four years ago," Gardner said.

"We're all disappointed. Don't by any means think that we're satisfied with it.

"We all believe we could have done better. But certainly looking to next year and the years after, there's a lot of reasons to be confident.

"I think there is a lot for our fans to be positive about."

Asked what would be a realistic target for 2022, Gardner replied: "I think every club aims to be a top-four club, and certainly that's where we'll be aiming.

"But for us, if we can finish better than seventh, that would be a good result ... our goal is for this team to emulate the Knights of 1997-2003, who were in the semis consistently. That's the challenge. We want to be successful for a long period of time."

Gardner said Knights coach Adam O'Brien had "absolutely" repaid the faith shown in him at the start of the season, when his contract was extended by a further two seasons. Unproven as a head coach when he joined Newcastle at the end of 2019, O'Brien has now steered them into back-to-back finals series - a feat the Knights had not managed since 2002-03.

They have not finished in the top four since Andrew Johns's last full season, 2006, although Wayne Bennett in 2013 steered them to a grand final qualifier after finishing seventh in the preliminary rounds.

Gardner said the Knights hope to bolster next season's squad with some strategic signings, to join Dane Gagai (South Sydney) and Adam Clune (St George Illawarra)