Michael Monaghan says Manly are not going to fall into the trap of focussing solely on stopping North Queensland star Johnathan Thurston in Saturday's NRL preliminary final.

While Manly duly recognise the champion halfback is key to the Cowboys' success, Monaghan says the Sea Eagles cannot afford to direct all their attention to the two-times Dally M player of the year.

The Sea Eagles hooker says fullback Matt Bowen, opposing rake Aaron Payne and a host of lesser known Cowboys also have the ability to turn into match-winners at the Sydney Football Stadium.

"We're not going to be surprised by anything they throw up," said Monaghan.

"Thurston has been one of the best players in the competition in a while and so has Matty Bowen.

"We know what to expect, it's just a matter of shutting it down and making sure we show respect to their whole side not just two blokes.

"I think (Payne) is one of the best hookers in the competition and we certainly won't be taking him or anyone else in their side lightly.

"We talk about how well Thurston and Bowen are playing but unless their forwards give them time and space they won't be able to do that.

"The guys in the middle are certainly doing something right and Payne is certainly playing well too."

Manly forward Anthony Watmough says the Sea Eagles have learnt their lesson from under-estimating North Queensland earlier this year.

In the only clash between the two preliminary finalists this season, the Cowboys stunned the Sea Eagles 30-26 in Townsville in round seven to end Manly's unbeaten start to 2007.

North Queensland led 30-10 before conceding three tries in the final 10 minutes, but it was the nature of the Cowboys' four-pointers which concerned the Eagles.

Manly have prided themselves on a committed defence all year, but the Cowboys still managed to score five tries all through their talent-laden backline.

Manly only missed 22 tackles that night, their fifth best effort of the season, but it was North Queensland's ability to capitalise on every line break or half opportunity that caught the Eagles by surprise.

It was the first time Manly's defence had come under fire all season and it's a constant reminder to the Sea Eagles how a lack of concentration can quickly turn into points conceded.

"We leaked 30 points last time we played them and the boys weren't too happy about that," said Watmough.

"I think they definitely caught us a little bit unawares up there so we're not gong to fall into that trap this time."

While Manly will spend part of their preparation pouring over the video from that last clash, Monaghan says any previous encounters count for little on Saturday.

The Cowboys will field a vastly different forward pack, while the Eagles too have several inclusions including Steve Menzies and Steve Matai.

"I can't even remember the game, but I think we're a much better side than we were in round seven and I'm sure they're a better side than they were in that game," he said.

"It doesn't matter what your name is come semi finals, as long as you get the job done and they've been doing that.

"We're confident with the side we've got and confident we can break them down."

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