Halfback Adam Clune had his best NRL game so far, while Matt Dufty again starred as the Dragons' fired to their biggest win in almost 15 months.

Among the competition favourites when Trbojevic went down, Manly fans now have serious cause for concern.

They are 10th in the ladder and have lost three straight for the first time since Des Hasler's return as coach.

They still have at least another three weeks without Trbojevic and five-eighth Dylan Walker, while they are also missing stood-down hooker Manase Fainu.

Suspended forward Addin Fonua-Blake will also miss Saturday night's date with top-of-the-table Parramatta in what shapes as a crucial clash for the Sea Eagles.

With Trbojevic and Walker watching on, Manly completed at just 70 per cent as captain Daly Cherry-Evans endured a rough night with three errors of his own.

Despite the Sea Eagles' injury problems, Hasler refused to blame the loss on his club's high-profile casualty ward.

"I don't think being down on injuries contributes to making too many errors with the ball," Hasler said.

"We're just not completing for long enough and that's not going to change unless we fix it."

There was plenty to like about the Dragons, who have now recovered to a 3-5 start to the year and sit 11th, just one win outside of the eight.

Ben Hunt started for the first time at hooker and played 80 minutes in the middle and out of dummy-half as their spine begins to take shape.

Clune is also looking more settled at halfback alongside Corey Norman, while Matt Dufty was impressive at the back.

Paul Vaughan got through 228 metres up front, while fellow forward Josh Kerr got his first try of the year when he crashed over after 27 minutes.

That put the Dragons up 6-4, before Dufty crossed four minutes later for one of the more bizarre tries of the weekend.

After Cherry-Evans burst through for Manly, he looked in on the line before he threw a ball straight back to Dragons centre Zac Lomax.

Lomax broke down field before finding the right man in Dufty to scoot away and cross at the other end of the ground.

It was one of two intercepts taken by Lomax for the match, as he also crossed for one late on when he latched onto a Cade Cust ball 50 metres out.

Clune and Norman also combined for a late try, with Clune providing a banana-kick back infield for his five-eighth in the dying minutes.

"Adam Clune is the one we're not talking about in the spine (finding form) at the moment," Dragons coach Paul McGregor said.

"He's making that jumper his own.

"It's very hard to move a young guy who is improving on a weekly basis."

Centre Euan Aitken put the icing on the cake with a third Dragons try in the game's final eight minutes, crossing on the siren after Brendan Elliot dropped a high Corey Norman kick at the back.

Their other try came when they were able to capitalise on Manly going a man down, with Zac Lomax putting Mikaele Ravalawa over with a flick pass on Jorge Taufua's vacant wing.

Australian Associated Press