Mitch Marsh continued his eye-catching Ashes audition on Thursday, scoring 169 as Australia were bowled out for 562 by Essex.

Marsh has been running drinks for Australia since being dropped for Shane Watson during the World Cup.

But having started his tour of England with back-to-back tons, the 23-year-old might be set for a role reversal when the Ashes start on Wednesday in Cardiff.

Darren Lehmann noted last week it would be a “tight” call as to whether Marsh or Watson featured in the series opener.

It became a whole lot tighter in Chelmsford, where Marsh dominated the early stages of the four-day fixture.

The allrounder pushed the tourists from 4-204 to 9-489, with the four-hour dig finally ending on day two when Matt Salisbury uprooted his off stump.

“It’s been great to get an opportunity,” Marsh said after finishing day one on 136.

“I’m not putting any pressure on myself … if you take enough wickets and make enough runs, the selectors are going to pick you at some stage.

“I’m just enjoying it and it’s a privilege to be on this tour.”

There was little more Marsh could have done to turn up the heat up on Watson during the UK’s hottest July day on record.

The runs kept coming in cooler conditions on Thursday, when Marsh motored past 150 with a couple of sweetly timed drives.

“I think I have matured; the coach might not think the same thing,” he said.

“As you grow up, I think you start making better decisions on and off the field.”

There were lives on 13, 98 and 128.

But Watson, who scored 52 and chopped on a wide ball from Ryan ten Doeschate, also received a reprieve on 10.

Marsh’s only big error was being responsible for a mix-up that ended Adam Voges’ innings.

“I almost ran (Peter Nevill) out, too,” he said.

“Maybe it’s a few nerves … I owe my Western Australia skipper a beer, I think.”

Last week, Marsh blasted a 93-ball century against an impotent attack on a docile pitch, when the game against Kent had already become a glorified training session.

It was an incredible display of power hitting – Marsh reached triple figures by scoring 77 runs in the same time Watson managed five.

This time around, he was more respectful early as the contest still had a bit of sting in it after Michael Clarke’s golden duck.

But that had well and truly changed on Thursday, when Peter Siddle and Nathan Lyon put on a final-wicket stand of 73 runs before lunch was taken.