Canberra halfback Sam Williams denies the Raiders' NRL clash with cellar-dwellers Parramatta is a must-win game but admits it comes pretty close.

The Raiders are desperate to arrest a three-match losing streak on Sunday against the Eels, who are reeling from four straight defeats and their worst start to a season in more than half a century with just one victory on the board in 2012.

Pressure is mounting on Raiders coach David Furner and his men, who have won just three games this season and sit fourth last on the ladder, but Williams sees Sunday's clash at Canberra Stadium as an opportunity to get their campaign back on track.

"It's probably getting fairly close to must-win, but I think there's still time in the season after it," he said on Friday.

"It's just a massive game for us in terms of confidence, particularly before the bye.

"You don't ever want to lose going into the bye because it gives you another week to think about what happened and you just don't want to be in that position."

Williams, who will play just his third NRL match for the year on Sunday after getting the call-up following a season-ending knee injury to captain Terry Campese, said the Raiders are taking positives out of last week's 18-12 loss to defending premiers Manly.

The Raiders produced an improved defensive effort against Manly after leaking 74 points in the two games leading up the Sea Eagles clash against Brisbane and Cronulla.

Williams said Canberra were wary of the Eels' unpredictable attacking duo of fullback Jarryd Hayne and halfback Chris Sandow.

"It's just making sure we're on-song defensively," Williams said.

"The danger with the Eels is that you don't know what to expect.

"They can fire if you say fire and they can be one of the best sides in the competition, so we've got to be really careful.

"There's a fair bit of strike power there and a lot of creativity."

Furner has stuck with largely the same side for the past three weeks, with Josh Dugan and Shaun Fensom both making steady improvements after returning from injuries.