It is all to play for in Melbourne.
The Wallabies have 80 minutes to save the series, while the British and Irish Lions can clinch back-to-back campaigns in Australia with a win at the MCG.
Almost 100,000 fans are expected to pack into the famous arena in a huge clash for both parties.
Both sides have made changes following the Lions’ 27-19 win in Brisbane last week.
Joe Schmidt has called on Rob Valetini and Will Skelton who have both recovered from injury and will add some much needed physicality to the Wallabies’ pack. Dave Porecki replaces Matt Faessler in the front-row.
The backline is unchanged with Schmidt sticking with Jack Gordon at scrumhalf despite calls to promote Tate McDermott to the starting lineup.
Andy Farrell has also made slight adjustments to his forwards. Ellis Genge drops to the bench with Andrew Porter coming in to complete an all-Irish front-row.
Ollie Chessum comes into the second-row alongside England teammate Maro Itoje, replacing Joe McCarthy.
There is just the one change in the backline with Bundee Aki replacing the injured centre Sione Tuipulotu.
Meanwhile, Owen Farrell is set to win another Lions Test cap off the bench.
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