Broncos winger Jamayne Isaako.

Even at 30-18 up with 20 minutes to go at 1300Smiles Stadium on Thursday, Broncos coach Wayne Bennett knew his team wasn't safe.

The veteran coach has seen enough Johnathan Thurston-inspired comebacks to know the game is never dead and the Cowboys did it again with a 34-30 win

"No, never against the Cowboys, they always have that ability to come back," Bennett said.

"I wouldn't have thought we did enough until the fulltime siren went.

"The effort was there, I'm not critical of our effort, but 46 per cent ball control [in the first half] and all the things that we could have done so much better and they just kept turning up."

It was a credit to the Broncos' effort that they were only two points behind at the break and they stormed out of the blocks in the second term to lead by 12 after Korbin Sims and Tevita Pangai had scored.

"Our forwards were as dominant as I've seen them play so there's some good signs but at the end of the night we didn't get what we wanted," Bennett said.

What they wanted was a win to join the Panthers and Dragons on 28 points and to make Sam Thaiday's 300th game a memorable one.

What they got was a second shock loss to a lower ranked opponent in the space of a week and a serious wake-up call ahead of a massive home game against the Rabbitohs next week.

Despite the personal disappointment, Thaiday wasn't about to push the panic button.

Sam Thaiday leaves the field after his 300th game.
Sam Thaiday leaves the field after his 300th game. ©Dave Acree/NRL Photos

"There were some good things out there we've just got to string them all together," he said.

"We shot ourselves in the foot a fair bit. Late tackle count penalties when they're coming out of their end are always going to hurt you and the Cowboys are set-play specialists.

"They play a lot of footy off the back of [their forwards] especially big Jase [Taumalolo]. Any quick play the ball they've got some good shape off the back of that."