Todd Payten believes his side's easy start in going 12-0 up against Manly may have caused the players to mentally ease up in the belief the points would keep flowing.
The Cowboys were handed some easy chances early on in their eventual 50-18 loss at 4 Pines Park on Friday evening with a Manly error in the opening set and a try from a kick following by some more leg-ups and another try to lead 12-0 after 10 minutes.
From that point on a lack of physicality in the middle and some very poor end-of-set execution brought the Cowboys undone against an in-form Manly outfit.
"Twelve-nil, I didn't think we had to work too hard for our lead," Payten said.
"We got a couple of ruck infringements on their line, a try from a kick which was nice skill but from there I reckon we just thought it was going to happen for us and didn't have the right physicality and right mentality with what we were doing with the ball at the end of our sets."
Match Highlights: Sea Eagles v Cowboys
He admitted it was a tough night for club debutant Tom Dearden but praised the former Bronco's commitment behind a beaten pack.
"It was (tough), he played behind a pack that was comprehensively beaten so the kid tried," Payten said.
"A couple of times he probably tried to over compensate but that's the way he is, he's a competitor. Made his tackles. He'll improve."
There were some new combinations with Tom Gilbert playing wider to accommodate the return of Jason Taumalolo and Lachlan Burr in the middle while Justin O'Neill was recalled for Origin winger Kyle Feldt and switched straight to the centres.
Tabuai-Fidow finds space on the left
"Tommy Gilbert hasn't been in the edge back row for a number of weeks and Tommy (Dearden) is new to the team," Payten said.
"The decision to put Justin in the centres instead of the wing because Javid has more experience as a winger and Justin's had more experience as a centre, that's what happens when you've got new combinations. Again, we'll improve.
"We just went away from the things that were working for us beforehand.
"We built our game on completing high, kicking to the corners, controlling where we gave the opposition the ball, working hard with our line speed and our tackling.
"It was a really good lesson for us tonight. It was a reality check and a chance to recover as a team. We've got another game on Friday night at home."