Warren Gatland's Lions reputation 'on the line' - Gwyn Jones

Warren Gatland's British and Irish Lions coaching reputation will be on the line in Saturday's decider against Australia, says ex-Wales captain Gwyn Jones.

The teams are tied 1-1 after the Lions won the series opener and the Wallabies took the second Test.

Jones says Gatland must ponder changes beyond those forced by injury.

"The final Test... will define Warren Gatland's coaching career with the Lions," said pundit Jones.

The former Llanelli and Cardiff flanker, whose career was ended by a serious neck injury in 1997, believes Gatland is likely to replace injured skipper Sam Warburton with Ireland's Sean O'Brien.

But he says if fit, England prop Alex Corbisiero (calf) and Wales centre Jamie Roberts (hamstring) should come in.

Jones would also select Wales number eight Toby Faletau ahead of Ireland's Jamie Heaslip and Wales hooker Richard Hibbard's added scrum power over England's livewire Tom Youngs.

And Jones also says England lock Geoff Parling, who took over from injured Irishman Paul O'Connell (broken arm) for the second Test defeat, should also make way.

"I think Parling is lightweight and ineffectual as a second row so I wouldn't be surprised if there's a change there," said Jones.

"And I think if you're going to pick a big team to scrimmage Australia to win the final Test, I think Hibbard probably comes into the reckoning.

"And for me, I think Faletau has been the better eight than Heaslip.

"But then you're making seven changes to the team for the final Test, the deciding Test; and the Test, really, that will define Warren Gatland's coaching career with the Lions.

"And that's a big gamble to make for 80 minutes of rugby - to completely change half your side.

"I don't know if we'll see that many changes, but there will have to be at least four or five.

"He's not that much of a gambler. He's bold occasionally with individuals."

Jones doubts the Lions will change their powerplay approach - dubbed "Warrenball" in the Australia media - or that Warburton's Wales open-side rival Justin Tipuric will earn a Test start.

"The natural replacement for Warburton would be O'Brien, who plays the same type of game as a competitive tackle-area seven rather than the more open and looser player that Tipuric is," said Jones.

"Having said that, the last game anyway was run by Australia.

"It was open, it was fluid and in those sorts of environments I think that Tipuric would be more effective.

"But I doubt whether he'll get the start."