Seen as the pinnacle in rugby union, Sam, captain and only the second player to skipper successive Lions' tours, will lead the Lions out for the Test decider against New Zealand tomorrow morning (Saturday 8 July, 8.35am UK).
The All Blacks won the First Test 30-15 at their famous Eden Park stadium in Auckland but Lions responded magnficently with a 24-21 victory in Wellington last weekend.
Now for the decider, back at Eden Park. Victory would mean only Lions' second-ever Test win in New Zealand, dating all the way to their first tour in 1888. The one and only series win n New Zealand was in 1971.
Below: Sam takes on the All Blacks last weekend
The scale of the task can be simply underlined like this - the All Blacks haven't lost at Eden Park since a France victory 23 years ago, July, 1994 - 39 Tests.
Sam tasted Test success as a Lions skipper in the last Test series against Australia in 2013, but he feels victory on Saturday would top the lot in his career.
“It is definitely the biggest challenge we have had in all of our careers including previous Lions tours, World Cups, Six Nations and all the big games in Europe the lads have been involved in," he said.
“It’s a massive, massive team effort, and so if we win it, it definitely will be up there as the pinnacle of our careers.”
Sam - a former schoolmate of Gareth Bale at Whitchurch School, Cardiff - told us how he came to support Spurs back in 2013.
"My father was born in London and brainwashed me and my twin brother Ben to support spurs from age six when I got my first shirt. He would always tell me 'you're Spurs in the blood now boys!' He had supported Spurs most of his life too."
Below: Sam interviewed pitchside at the Lane
Now 28, Sam became the first Welshman to captain the Lions since Phil Bennett in 1977 when he took the armband for the Australia tour in 2013. He performed superbly as Lions won the first Test 23-21 before narrowly losing the second 16-15. He was injured for the third Test where Lions ran out 41-16 winners to clinch the 2-1 series victory.
Capped 75 times by Wales, he first represented his country in 2009. He captained Wales for the first time in 2010 and led them at the 2011 World Cup, where they reached the semi-finals. Wales then clinched the Six Nations' Grand Slam (winning all five matches) in 2012, retaining the title in 2013.