NSW five-eighth Jamie Lyon faces an anxious wait ahead of State of Origin II after injuring his ankle as Manly just held on for 24-20 NRL victory over the North Queensland on Saturday night.

The centre limped off the Diary Farmers Stadium pitch in the 49th minute with a suspected high ankle sprain and could not return, putting him in doubt for the second game of the series in Brisbane on June 16.

The loss of Lyon took some of the shine off debutant winger Dean Whare, who laid on a hat-trick of tries on debut, laying the platform for a win.

But Manly did everything they could to throw away a 24-6 lead in the second half, the Cowboys launching a second half assault that fell just short.

Virtually-unknown St George junior Whare was called up from the under-20s after the late withdrawal of half Kieran Foran who failed a fitness test on his injured hamstring.

By the 28-minute mark he had vindicated coach Des Hasler's decision to select him with his three tries setting up an 18-point lead.

The St George product was into the action after just six minutes, taking advantage of a sweet Lyon ball to beat Will Tupou, who was called up for the Cowboys from the under-20s in favour of Michael Bani.

Four minutes later, he was the recipient of an unusual try from video referee Phil Cooley after Michael Robertson pushed the ball down when Whare seemed destined to be held up.

Then he took the aerial route in the 16th minute, out-leaping opposing winger Ashley Graham to complete the treble.

A Michael Robertson try in the shadows of halftime appeared to signal the end of North Queensland, but they had other ideas heading out of the sheds after the halftime siren.

Skipper Johnathan Thurston, backing up from a man-of-the-match performance for Queensland, sparked into life but in the end the Cowboys lacked the finesse to finish off a series of dangerous movements, butchering at least four try-scoring opportunities.

A brilliant try to Will Tupou spread from Thurston through Tonga started the comeback while prop Leeson Ah Mau showed plenty of toe in the 62nd minute with a blistering 45 metre run down the sideline which set up Graham in the right corner.

Then when former Cowboy Ben Farrar spilt a Thurston bomb, Luke O'Donnell capitalised and charged over to set up a nervous final eight minutes.

Manly coach Des Hasler refused to speculate on the extent of Lyon's injury, with scans scheduled for Monday.

But he heaped praise on Whare, who was plucked from the St George nursery by Noel Cleal.

"It was a fantastic debut," Hasler said.

"That's why this game of rugby league is so good, to see another young talent come on.

"I thought he grabbed it with both hands, he was really good for us tonight."

Hasler also commended his players' efforts on holding on for the win with fatigue wracking the group in the final stages of the game.

"I think it was a pretty courageous effort," he said.

"There were a number of players backing up from the Origin on Wednesday night, a bit of illness in the camp, late withdrawals.

"In the second half we lost key players ... they just kept turning up for each other."

For Cowboys coach Neil Henry, it was a shattering way to notch up another loss and he lamented the club's lack of class in attacking the line with all the possession in their keeping.

"We created a lot of opportunities with some good attacking footy but we just couldn't nail it at a few crucial times," he said.

"When you create opportunities you need to get across the line. It's as simple as that.

"I was disappointed with our start again but I thought we had done enough there to come back and win a game."

Brought to you by AAP © 2024 AAP