With Farren Lamb, the man that nailed that decider dagger for the Magpies in 2018, sitting in the stands at Spooner Oval on Sunday - he helped his new club Oberon to a convincing win over St Pat's in Bathurst the day before - Fishies five-eighth Alex Bonham nailed a telling field goal with five minutes remaining to seal a 29-22 victory over the premiers.

CYMS trailed 16-12 at the break and then 22-12 three minutes into the second half after Ben Maguire barged his way over under the sticks for Forbes' fourth try of the game.

But from that point on Jarryn Powyer's outfit wrestled their way back into the contest and then stormed over the top of the Magpies in the final 15 minutes to remain the only side undefeated after four rounds of the 2019 season.

"It was a little bit sweet," Bonham smiled when asked about nailing the field goal late in the game.

"We were six up so thought we'd go up by one more to put a bit of pressure on them again. It ended up working out well."

Bonham said reducing his side's errors and eliminating the silly, late-in-the-tackle-count penalties helped get the Fishies back in the contest.

"We just had to take the pressure of ourselves," he added, Sunday's clash just the star playmaker's second in the top grade this season.

"I had to earn my spot. I had an off pre-season, getting married and stuff. I had a bit of time off and Jazz let me have that time but he said I had to work hard to get back in the team, which I have been working hard. He's been pushing me."

Much like the premiers pushed CYMS, especially in the first 40 minutes.

The Magpies looked slick in the opening period and tries to recruit Josh Toole, winger Warren Baxter and then Mitch Burke shot the premiers out to a 16-6 lead, Jyie Chapman's opening try of the match looking a distant memory for a visiting CYMS side on the back foot after 28 minutes.

Cameron Dennis strolled over for the easiest try he'll score in 2019 just before the break and Bonham's conversion reduced the deficit to four and gave CYMS a sniff at half-time.

Despite Maguire scoring early for Forbes, it was an invitation the Dubbo club gladly accepted.

Billy Sing barged his way over in the 53^rd minute before Kaine Rapley's four-pointer outwide - and the cracking sideline conversion from Bonham - leveled the scores at 22-all.

With 13 minutes to go, Chapman found space and he hit Corey Drew back on the inside to score the go-ahead try before Bonham iced the crucial road win with a late field goal.

Forbes mentor Cameron Greenhalgh lamented his side's second home loss of the second, the first another "game that got away" in round one against Nyngan, the Tigers' a 20-10 victory a month ago.

"We did enough to win that game but we got them back in the game with some lazy stuff," Greenhalgh said.

"We can't dwell on it, we need to be better."

The premiership-winning coach added he was impressed with his side's opening 40 minutes but errors proved costly with the game on the line and with crunch games against Wellington and Parkes looming for the defending champions, those sort of mistakes could mean the Magpies battle to keep touch with the top three.

"We've got to play these sides (Nyngan and CYMS) on the road, and there's two games (at home) we've let slip that we really needed to keep us near the top of the ladder," Greenhalgh said.

"We started the second half well and got points on the board and 10 points in front, against CYMS, on our home ground, it's enough to win.

"But you can't put the gun in the holster against these boys, they keep trying to score points the whole time and to their credit them came back. They scored some soft tries that should't have been scored."