GRIFFITH'S Southern Inland premiership credentials will be put to the ultimate test over the next month with a gauntlet of matches against the competition's pacesetters.

The undefeated Blacks face top side Wagga Waratahs tomorrow, before taking on second-placed Charles Sturt University for the Ben Groat Cup next week and third-placed Albury after the June long weekend.

"This will definitely tell us where we're really at," coach Seru Rogo said.

"The boys are really looking forward to it but we're keeping our feet on the ground and just looking forward to the task ahead."

Rogo said the Blacks turned their attention to the 'Tahs game - this week's SIRU match of the round - as soon as the siren sounded on Griffith's 31-17 defeat of Temora on Saturday at the Coro Club.

"After the game on the weekend the boys were already talking about Waratahs," he said.

"That just shows how much they like playing the big games."

Rogo will be counting on the big-game experience of Marika Vunibaka and Dan Rawaqa for tomorrow's trip to Wagga.

The former Fijian internationals have done the business on rugby's biggest stage and will be key to keeping the rest of the Blacks squad grounded over the next three weeks.

"We're very fortunate that we have those players around us this year," Rogo said.

"The boys tend to lift every time they're around - it's just the little things they do on the field.

"They all add up and make it easier."

However, the Blacks will be missing one of their best and most battle-hardened players tomorrow in Daniel Dowson.

The Griffith skipper has led from the front all year but suffered a concussion against the Tuskers and will not be risked.

"It's not going to be good for him or for the club if we do that," Rogo said.

"He may be one of our best forwards but when it comes to concussions, it's a big no-no (to rush him back)."

Daniel McGreal has been named as his replacement, with that straight swap leaving Rogo confident the Blacks will not be lacking much despite the absence of their captain.

The Waratahs were ruthless on the weekend, tearing apart the Leeton Phantoms in an 85-3 bloodbath that saw them retain top spot.

Rogo, however, has promised his Griffith side is very well prepared for what the Wagga side has in store.

"They're a very well-coached side, very well-structured," he said.

"Their forward pack is pretty mobile and they're going to concentrate on playing in the forwards a lot, from what I know.

"We've spoken about it at training with the boys and everyone knows what their strengths are."