AAP

Less than a week after announcing themselves as a genuine premiership contender, Cronulla skipper Paul Gallen labelled the Sharks "soft" after becoming the latest victims in North Queensland's surge towards the NRL finals.

And worse to come for the Sharks - they could be without Gallen for their sudden death final after he was put on report for a crusher tackle.

The Cowboys won for the fifth straight time, veteran fullback Matt Bowen - who on Friday announced his NRL career would be over at the end of the season - turned back the clock with a vintage performance in the 31-18 win on Sunday.

It left North Queensland needing just to beat Wests Tigers on Saturday night to confirm a finals spot, and they now seem a more dangerous finals proposition than their vanquished opponents, who struggled to go with the desperate Cowboys.

Coach Shane Flanagan refused to use the emotional drain of last Monday's epic win over then ladder-leaders Sydney Roosters as an excuse, Gallen admitting his side had gone backwards.

"It was a poor performance, it was really soft to be honest," Gallen said.

"It's no excuse the way we played Monday night and then to turn up and play the way we played today, that's why we're running fifth or sixth and the top four sides are where they are - they do it every week.

"You can't perform like we did last week and then go backwards and we did.

"We went backwards in a big way, the way we defended today."

While the performance may have been poor, the Sharks didn't have much to gain by way of winning on Sunday - the side assured of a home final for finishing either fifth or sixth.

There was also no Todd Carney, who was scratched after straining his hamstring in the side's last training run on Saturday.

He should be back on deck on Sunday against Canberra, but Gallen will have to wait on the match review committee's findings, after an awkward tackle on Scott Bolton.

Anything greater than a grade one dangerous contact charge would wipe Gallen out for the opening week of the finals.

"I was surprised it was a penalty at first, I didn't know what it was exactly for at first, I was just trying to get him on his back," Gallen said.

The match was nip and tuck the whole way, rival backrower Jayson Bukuya and Gavin Cooper scoring doubles for their respective sides.

The genius of Bowen was the difference, as he scored one try and set up three others.

However it wasn't until Johnathan Thurston's 78th minute field goal that either side led by more than a converted try.

Thurston admitted belief within the group was growing.

"Definitely, we've been putting ourselves under the pump throughout games but the belief to defend our errors is amazing," Thurston said.

"It's coming at the right end of the year, it's taken a lot longer that we would have liked but it's good to be winning."