The Rams were outgunned in the second half at Parkes' Pioneer Oval on Sunday, losing 40-18 to the Monaro Colts.

Western led the game until the 40th minute as Cooper Black dominated, scoring two tries before the Colts fired back before going on to run in four tries to seal the win.

"It was a tough one to take, it was there for us to win today," Western coach Shane Rodney said.

"It started off not too bad, the boys were just lacking a bit of energy and belief. When a few things went against them, Monaro who are a good team got a roll on and we couldn't contain them.

"It's a short comp, we needed to acknowledge the stuff from today and move on quick

"We've got Illawarra next week who are a very good team again. For us at this point, because we've had two losses and a win, every game is a must-win."

Rodney's group got off to a flying start with tries to Nathaniel Robinson and Black early but Monaro hit back twice just before halftime to lock up the score at 10-all.

Black scored his second four-pointer of the day after executing a clever one-on-one strip close to the line.

Just as Western was set on scoring again, Monaro's James Croker turned the game on its head.

The Colts fullback caught Western off-guard, taking a quick tap on his own 20m line before running the length of the field, a moment which lifted his side.

"He knows how to move, he's got some good speed," Monaro captain Joseph Elton said.

"That turned the game for us and after that, we just fed off our own energy which was really good."

Croker's runaway try flipped the script for the match with Elton scoring of the Colts' final four tries.

"It was a really good win, we had a bit of a shaky start," he said.

"But once we started to find our front a bit and give away less penalties we were able to capitalise.

"Once one (guy) sort of got going we started to play good footy.

"We are just really upbeat and once we get going, no one can really stop us so hopefully we can replicate that next week."

MONARO COLTS 40 (Lachlan Cunanan, Toby Ferris, James Croker, Harry Hudson, Joseph Elton, Alex Hardy, Jonah Anderson tries; MItchell Brophy 6 conversions) defeated WESTERN RAMS 18 (Cooper Black 2, Nathaniel Robinson, Tully Howell tries; Black conversion)