He's within reach of a maiden NRL premiership but Bulldogs prop James Graham is still at a loss to explain his side's dramatic form reversal after limping into the finals four weeks ago.

After setting the competition alight over the first half of the season, the Bulldogs slumped to just two wins from their final eight games to sneak into seventh place on the ladder.

After a remarkable capitulation to the Gold Coast in round 26 in which they surrendered an 18-0 lead to go down 19-18, the Bulldogs were expected to be cannon fodder for a star-studded Melbourne outfit in week one of the finals.

A 28-4 boilover marked a sharp form reversal that's held through tight wins over Manly and Penrith to book themselves a spot in Sunday's grand final.

Asked what brought about the turnaround, a frank Graham said: "I wish I knew the answer to that because honestly I don't know.

"We went to the Gold Coast and prepared exactly the same as we did for the trips to Melbourne and then we prepared exactly the same for Manly.

"I honestly wish I could tell you something we've done or something we've changed or something Des [Hasler] has said but he's been banging the same message into us for however long now ... since November."

Graham, arguably the player of the finals so far, said his side never lost faith in their ability to grind out wins come finals time.

"We showed throughout the year the performances that we can put out there," he said. "You can read too much what happens at the start of the year.

"We've seen this year how many different teams have been number one on the ladder and who's been in the top four and how much it's chopped and changed.

"We've shown in parts what we can do and I guess it's just about getting yourself into a position to play in September and we did that. We got ourselves into a position and finding form at the right time of the year."

Since the NRL introduced an eight-team finals series, no team has finished in the bottom four and gone on to win the grand final.

That fact combined with the Rabbitohs' red-hot form heading into the decider leaves the Bulldogs as underdogs.

It's a position historically embraced by coach Hasler, who will oversee his fifth grand final in eight seasons on Sunday, but Graham said it won't factor into his side's preparation.

"Odds and underdogs and all that hurrah is something bookmakers and experts and whatnot want to talk about but we just look to try and go on and win this game."