Hugo Keenan etched his name in British & Irish Lions legend with a late try to seal Qatar Airways Lions Men's Series glory in match for the ages in Melbourne.

You don't need to ride the rollercoaster at St Kilda's Luna Park, just come a few miles down the road to the MCG because this instant classic was a white knuckle thriller.

A record crowd for a Lions Test of 90,307 lived and breathed every moment of a match that ebbed and flowed and wasn't decided until the very last second.

The Lions trailed 23-5 at one stage but took the lead for the first time in the match when it mattered most, prevailing 29-26 in a titanic clash which represented Test match rugby at its best and purest.

WALLABIES START STRONGLY

Wallabies coach Joe Schmidt had made the simple demand for more intensity after the hosts were left reeling by the Lions’ fast start in Brisbane.

It took Australia nearly half an hour to breach the tourists' 22 last week, but they had clearly listened to the boss, winning statement early collisions as they sprung from the traps.

Much has been made this week of the return of Rob Valetini, and he made two big early carries as Tom Lynagh slotted a straightforward early penalty.

Will Skelton, also back in the team after missing last week through injury, was also proving a constant nuisance at the breakdown, the Lions surrendering another penalty that Lynagh again threaded from distance.

But perhaps a fired-up Skelton took things a little too far, testing the patience of Italian referee Andrea Piardi.

His physicality only seemed to wake the Lions. Jack Conan dropped the ball to see a try chalked off, while moments later full-back Keenan was taken down inches short.

Dan Sheehan finally converted the pressure into points, powering over from close range, with Finn Russell uncharacteristically failing to add the extras.

“The Power of One” was Saturday’s front-page headline in Melbourne’s Herald Sun, with Valetini returning for the biggest match of his career in the sports-mad city where it all began.

A local journalist once described the then-teenager as “hitting like a freight train while still learning to drive”.

Over 50 international caps later, he still hits as hard but with a lot more miles on the clock, his bruising presence helping Australia break their rivals defensive line at will.

James Slipper, at 36, is the only Wallaby to have played in the last Lions tour here 12 years ago and he grabbed Australia's first try — compounded further when Lions winger Tommy Freeman was sent to the sin bin.

The momentum was clearly with the hosts as they hit the disadvantaged Lions with a two-try sucker punch in the space of just three minutes, the MCG cauldron bubbling over.

First Jake Gordon sniped over, and then the dancing feet of Joseph-Aukuso Suaalii cut through the red rearguard before sending Tom Wright over.

Back at full strength, though, the Lions hit back with their own three-minute, two-try salvo. First, Conan spotted fellow back row Tom Curry for a simple score, and then Huw Jones battered past two defenders to reduce the half-time deficit to just six.

It was breathless stuff, the huge crowd grateful for the half-time hooter just to process what they had seen.

LIONS COMPLETE FAMOUS FIGHTBACK

Valetini made way for Langi Gleeson at half-time, his 40 minute contribution brief but impactful, while the destructive Skelton stepped out seven minutes later.

But despite the withdrawal of their two talisman, the Wallabies continued to exert the pressure, Lynagh converting a penalty to extend their lead beyond a score.

The much debated Lions back row were the foundation of last week's win in Brisbane and after Curry's first half score, Tadhg Beirne joined the fun. He lunged into the corner after James Lowe's smart pass, Finn Russell nailing the conversion to reduce Australia's advantage to just two.

After the blood and thunder of the first half, it was no surprise the second period was just a little less frenetic, though no less tense.

The final ten minutes was always going to be about the team that kept their discipline and, ultimately, took their chance.

The Wallabies were trying to slow things down but the Lions were relentless, Keenan crashing over the line and then surviving an anxious wait for confirmation after Wallabies captain Harry Wilson had cried foul.

It was a box office end to a thrilling spectacle. The Lions sights are now set on completing an historic 3-0 series win in Sydney next week.