The 23-point margin may have looked like a comfortable result but for 60 minutes it was an even and extremely hard-fought contest.

But after a gritty defensive effort the Roos were able to get their hands on the ball and play the attacking style they love and piled on the points in the final 20 minutes.

"It's really good and it's what we wanted all year," captain Shaun McHugh said after guaranteeing finals rugby.

"We were pretty even the first half but the second we were able to capitalise on some loose ball and some breaks in play."

Cowra captain Chris Miller was left disappointed after the match, aware his own side's path to the finals was now a whole lot more difficult, but said second half errors cost the Eagles.

"It would be interesting to see the possession stats for the first half because we really strangled them and went on with that momentum into the second half but they dominated on our mistakes and scored points off that and plenty of tries," he said.

Despite James Mata sitting out with injury and Filisione Pauta a late withdrawal the match could not have begun any better for the Roos with a try inside in the opening 30 seconds.

The ball was moved out to the right and winger Jacob Phillips sprinted down the line and produced a classic draw and pass to put McHugh over.

Cowra dominated the match after that and levelled up through a converted try from prop Evan Stanbridge but the Roos were soon back in front when Timmy Phillips dived over from close range.

The Eagles had all the ball again leading into half-time but could not make it count.

After receiving a penalty right on half-time the visitors opted to take the three points, something McHugh said was a big confidence boost for his side.

"Not too many teams have gone through us, they've had to go around us and we're OK with that," he said.

"It shows respect and when they took the three points before half-time, if I had that option I would have gone for the lineout because it's only half-time but I think that shows the respect our defence has got."

Cowra were strong at the start of the second half as well but a knock-on inside their own 22 led to a try to the lively Eli Kinscher and the Roos' lead was extended to 19-10.

The fourth try and bonus point was sealed shortly after when McHugh went in for his second and the match was virtually won five minutes later when Hena Tuatea sliced through and went over.

Tuatea then made a break on his own 30m line and with no Cowra player in sight he ran 68m before passing to Moa Kavaefiafi to put the icing on the cake.

Cowra eventually crossed again through winger John Clack but it was only a consolation as the Roos claimed one of their best wins of the season.

"It reminded us of that Bulldogs game, it was desperate footy," McHugh said referring to the recent 21-15 win over Bathurst.

"Last week we were lucky to score plenty of points but we were desperate again today and we play our best footy when we're desperate."

o DUBBO KANGAROOS 38 (Shaun McHugh 2, Tim Phillips, Eli Kinscher, Hena Tuatea, Moa Kavaefiafi tries; Tuatea 3, Anthony Golding conversions) defeated COWRA EAGLES 15 (Evan Stanbridge, John Clack tries; Aaron Denzel conversion, penalty)