Newcastle's play-off hopes, which had been tenuous for much of the season, were officially declared extinct after their 1-0 loss to Perth at HBF Stadium on Saturday night - a result that clinched the Premiers' Plate for the Glory.

Having finished runners-up last season, and after retaining the majority of that squad, Merrick's expectation was that Newcastle would again be involved in the business end of proceedings.

He said it was "very disappointing" to bow out of the finals race with two preliminary rounds remaining, because he felt Newcastle had enough talent to have performed better.

"We should have been in the finals," Merrick said.

"I think we're good enough to be in the finals, but we've only scored half as many goals as we did last year.

"It's pretty obvious that we've got to work in that area.

"We've got a good team. We've re-signed 16 players, plus another player [Matt Millar] from the Mariners, so we're keeping them together."

Merrick said Newcastle had the makings of "a good young squad" locked in for next season and some of Generation Next would be "blooded" in their next two games, against Brisbane (away) and Sydney (home).

"We've got five junior internationals - three Olyroos, one under-17 and one under-20 - and they're all beginning to show their ability," he said.

"So I think it gives us a good chance to set up for next year, with the continuity."

He added that he thought the Jets were "going to be a team that will regularly be in the finals and hopefully the top three ... but we don't score enough goals. That's what I have to fix next year."

He tipped Perth to win their first-ever A-League title this season, having secured top spot in the play-offs and home-ground advantage, should they qualify for the grand final.

"Congratulations to Perth," he said.

"I'm sure they'll do extremely well in the finals. They'll probably go all the way, actually ... the most consistent team has been Glory, by far. But there's no double chance any more."

He said Sydney and Melbourne Victory "haven't been anywhere near as consistent as Glory", but as Sydney discovered last season, the margin for error in the finals is slim.

Perth's Diego Castro, who Merrick described as "the Spanish guy that never ages", could be their wildcard in the finals.

"He's the fittest I've seen him," Merrick said. "He's running out the game. I can't believe he's defending as well as attacking."