For Gold Coast to cause an upset against Brisbane in Saturday's QClash, the biggest man on the Gabba knows he has to improve from last week.

SUNS co-captain Jarrod Witts had a rare down day against former club Collingwood, with Brodie Grundy getting the best of the ruck battles and steering the Magpies to the win.

Ahead of his 100th game, the 209cm, 111kg Witts said he is out to rectify his performance this weekend. 

"I had a disappointing and down game," he said.

"Grundy is a quality player and played really well, so credit to him.

"I'll be looking to turn that around.

"I'm coming up against another quality ruckman this weekend in Stefan Martin, who I think Brodie modelled his game on early days. They're quality opponents and I'll be looking to have an impact this week. 

"I'm looking forward to the challenge of responding and can't wait for Saturday arvo."

Witts has had a fantastic individual season, his first as co-captain, with Sunday's outing one of the rare times his colours have been lowered.

He said Jack Bowes, Ben Ainsworth and Jack Martin would all be better this week after returning from long injury lay-offs against the Magpies.

And they'll need to be against a Lions outfit that is on a seven-game winning streak. 

"It's a really important game for the footy club," Witts said.

"To Brisbane's credit they're going really well and deserve all the accolades they're getting at the moment, but rivalries are rivalries and we'll be going out there to stop them."