The "Thirsty Thirds" are the only Bowral side to qualify for the season's biggest game and they will have the support of the whole club when they run onto the field at 11.35am.

Third grade co-coach Stuart Fox said there is a positive feeling in the team heading into Saturday's game with all players looking forward to the challenge.

"It's a good feeling of excitement and anticipation and the boys are all looking forward to playing a good game," Fox said.

"I know what we have to do to win, now it's just a matter of doing it on the day."

Blacks made it through to tomorrow's big match after beating University 19-15 last week, in a dominant display from the forward pack.

The forwards will need to be on song again tomorrow against the powerful Shamrocks pack and Fox is predicting a very physical match played mostly in the trenches.

"They'll play a forward-orientated game plan and that's the way we like to play it as well," he said.

"So if we can get right on top in the forwards and engage them in the middle, then we should be able to get the ball out to our backs in some space."

University are a young and quick side who like to throw the ball around, while Shamrocks are an older team who play it tight and up the middle.

Fox said this type of style suits the Blacks as is evidenced by the results this year with Bowral winning both matches.

But those results will count for little when the whistle blows tomorrow morning, a fact not lost on Fox and his coaching partner Jason Silms.

"It's a different game all together when it comes to grand final day," Fox said.

"They'll definitely be stronger because they were missing four or five of their starting line-up the last time we played them."

Fox said the players are determined to win the title for the rest of the club and he has told them to relax and enjoy the experience of playing in such an important match.

"I told them to enjoy the day and don't let yourselves down by not giving your all," he said.

"Enjoy the experience because you don't get the chance to play in many grand finals so make the most of it."

BLACKS: 1 James Lowe, 2 Jason Buckley, 3 Scott Krebs, 4 Mark Freund, 5 Peti Fereti, 6 Neil Halliday, 7 Phill Fleming, 8 Jimmy Galbraith, 9 Matt Star, 10 Brad Withers, 11 Nui Teua, 13 Billy Deveril, 12 Danny Williams, 14 Robert Sams, 15 Mitchell Jones, Reserves: Mark Moore, Simon Neubert, Paul McTaggert, Nathan Lammers, Adam McNeill, Brett Acton.