A DESIRE to answer his critics and the relief of signing a five-year contract extension could be behind Nic Naitanui's upswing in form, says his West Coast teammate Jamie Cripps.

Naitanui produced his best performance of 2014 in the Eagles' eight-point loss to Collingwood at the MCG on Saturday.

On their own, the 201cm ruckman's numbers don't look especially impressive – he collected 17 touches, won 24 hit-outs, laid three tackles and won five clearances.

Rather, it was his desperation at the contest as well as his willingness to fly high and crash packs that hinted he might soon return to his best.

It was enough for Cripps to claim that his teammate, who has battled groin and Achilles issues, was "back to normal".

"He's back jumping on people and that's what we want him to do," Cripps told AFL.com.au.

"Just crashing packs and getting it to the ground, which he was doing. Chasing down as well…he was back to normal I reckon."

Few doubt the 2008 No.2 draft pick's prodigious talent, but Naitanui's apparent lack of intensity at times has frustrated West Coast fans.

Cripps couldn't put his finger on one reason in particular for the big man's turnaround against the Pies, but said finalising his contract extension and being stung by criticism might have something to do with it.

"I'm not too sure. He's probably pretty happy getting his contract done but yeah just the criticism as well – it would be all of it, I reckon," Cripps said.

"I am happy he's signed."

Cripps' disappointment at the gut-wrenching loss to Collingwood overshadowed his career-high three goals.

"It does (hurt), we were so close," he said. "We just weren't consistent with our footy for long enough and they were. 

"They just finished real strong and we couldn't keep up with them.

"We wanted to bring a four-quarter effort. We knew we could match them and at them, but we were just a bit unlucky in the end."

At 4-5, the Eagles can ill afford another blow to their finals aspirations when they face North Melbourne at Patersons Stadium in round 11.

"They got pretty close to Geelong in the end so that will be a massive game back home," Cripps said. "Hopefully we can get them."