By Michael Whiting

Gold Coast SUNS fullback Nathan Bock added another big scalp to his growing list on Saturday night when he kept in-form Collingwood forward Travis Cloke to just two goals.

Despite playing in a team with only three wins and sitting in 16th place, Bock has been a pillar in an under-siege Gold Coast defence this season, and it was no exception against the Magpies.

The 196cm and 108kg Cloke has taken 30 more contested marks than any player in the competition this season and been a menace to most defences.

At Metricon Stadium he had 21 touches and took 10 marks, but with the ball coming into Collingwood's forward 50 an incredible 78 times, Bock did well to push him up the ground for possessions and keep him to 2.1.

The 28-year-old's form is so good, GC SUNS coach Guy McKenna compared it to his 2008 exploits with Adelaide that earned him All Australian honours.

"To keep Trav Cloke – with 78 inside 50s – to keep the man mountain to that, I think Bocky's been fantastic," McKenna said.

"I remember seeing him in 2008 when he was in All Australian form and he's not far off it. Given the side he's in, it's an even better result I think.

"He's played on some big brutes and the best forward from the opposition and he's done a fantastic job and has done all year, under duress too. The first part of the season the ball was coming in on the forward's terms too, not his."

Bock has kept Barry Hall to two goals, Jack Riewoldt to one and Drew Petrie to one.

Bock has turned himself from a running 'loose man' defender into an elite one-on-one stopper and McKenna said his influence was best shown when he was not out there.

Playing against both Fremantle and Hawthorn with a gastro illness, Bock kept Matthew Pavlich and Lance Franklin to almost anonymous days until he had a quick sideline spell and they both capitalised with three goals.

"Maybe one or two games he lowered his colours but that would have been early in the season when the ball was coming into our back 50 like a hot knife through butter," McKenna said.

"(Defensive coach) Dean Solomon sleeps easy at night."