Did du Plessis's declaration actually help Australia?

Faf du Plessis's cunning move to prevent David Warner opening the batting has been praised as a masterstroke, but will it backfire?

The South African captain outsmarted Australia and Warner with a sudden declaration after the Aussie opener had left the field for treatment on an injury.

The Australian batsman had just returned to the field after a stint off for a period of time getting treatment on an injured shoulder.

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Under cricket's rules, a player must be on the field for the same time they spent off it before being able to bowl or bat again - in Warner's case, he was caught short.

The usual opener watched on as debutant Matt Renshaw and Usman Khawaja battled a swinging pink ball under lights for 12 overs, surviving to stumps at 0-14.

And there's the kicker - they did survive.

Former Australian Test bowler Stuart Clark reckons Warner's absence might have actually helped 20-year-old Renshaw.

"The worst thing that could have happened for him is for David Warner to come out and go 'four, four, four', poor old Matty Renshaw is 13 balls for none, the pressure's now building and building," Clark told Fox Sports.

"Usman (is) more calm and collected...and bats with him (Renshaw) at Queensland."

Clark didn't want to take anything away from du Plessis's genius play however.

"Maybe in hindsight it worked out (for Australia), but (it was) a good heads-up piece of play from Faf du Plessis," Clark said.

Instead of being forced to battle the tough late evening conditions, Warner now gets to enjoy the sunshine on day two, whenever he happens to get his chance.

with AAP