Mitch Marsh continued his strong showing in the opening game of Australia’s Ashes tour, snaring a wicket on day four.

Michael Clarke declared overnight at 4-322 in Canterbury, setting Kent a target of 550 in the four-day fixture that became a glorified practice session long ago.

Mitchell Johnson and Ryan Harris were unable to strike with the new ball.

Instead it was Peter Siddle who impressed the most in Sunday’s morning session, uprooting opener Joe Denly’s middle stump with a cracking delivery.

Legspinner Fawad Ahmed removed Rob Key, who was caught at wide mid-on.

Marsh then had captain Sam Northeast out edging a delivery as Kent reached lunch at 3-118.

On day three, Marsh heaped further pressure on Shane Watson with an aggressive century.

Clarke promoted himself, Watson and Marsh up the order – given all three men missed out on a big score in the first innings.

Watson crafted a score of 81 and it wasn’t as if the temporary first drop played poorly until picking out substitute Sam Weller in the deep.

The 34-year-old’s problem – aside from the niggle that prevented his bowling in this game – is that he was overshadowed by the other all-rounder in Australia’s 17-man squad.

Marsh smacked a terrific ton, belting five sixes and 12 fours – all but one of the boundaries coming after tea as the right-hander helped himself to 93 runs off 64 balls.

“There’s not much you can do,” Northeast said.

“It’s the Australian mentality, they’re very attacking players.

“They just keep running at you and running at you.”

To put the rampage in perspective, Marsh reached triple figures by scoring 77 runs in the same time Watson managed five.

He was particularly strong on the leg side and retired after the 102-minute masterclass.

“The boys couldn’t stop commenting on how hard he was hitting the ball,” Harris said.

“There’s two all-rounders pushing for spots and we saw them both bat beautifully today.”

Marsh’s maiden century for Australia was against an impotent attack on a lifeless pitch, but nonetheless adds further intrigue to the selection debate.

The duo’s showdown is one of many challenging decisions that national selectors must make before the Ashes starts in Cardiff on July 8.

Openers Chris Rogers and Shaun Marsh were both among the runs against Kent and will be hard to separate.

Harris, Mitchell Johnson, Mitchell Starc and Josh Hazlewood all have strong claims when it comes to the three pace berths.