It would be hard to describe this British and Irish Lions tour of New Zealand as a true classic, and yet it teeters on the edge of greatness, fuelled by the joy of surprises. The Lions and the All Blacks are heading for the finale that everyone dreamed of. Well, perhaps not everyone. The world champions will have been planning and expecting a whitewash.

One win apiece heading into a winner-takes-all decider at Eden Park in Auckland between the two most star-studded rugby union teams in the world is the stuff legends are made of and will ensure pubs on both sides of the globe are packed to the rafters.

New Zealand may wonder how they got here: clearly superior in the first test and with plenty of opportunities to win the second. In Wellington, the dismissal of Sonny Bill Williams and an off-day for Beauden Barrett ensured the series went to a decider.

This Lions team has surprised the world number one ranked nation on their own turf. When the All Blacks were beaten in an enthralling second test it was the first time they had been beaten at home for eight years and the only time they had been left tryless at home in 15. Williams' red card was the first such ignominy suffered by an All Black for half a century.

In the opening test the sheer audacity and brilliance of the Lions' opening try – beginning with the brilliantly unexpected sidestepping of Liam Williams, sweeping the length of the field to be finished by Sean O'Brien – confounded expectations of the tourists.

It was a move that showed the Lions capable of matching their hosts for skill and audacity. Perhaps the rest of the Test match played out as Steven Hansen and co expected, with the adventurous set-up of the tourists exposed by clinical Kiwi efficiency.

The second Test was certainly more of a surprise for the hosts who have won successive World Cups and have looked almost unstoppable since. For the Lions to score two tries to none was certainly unexpected.

Perhaps the biggest shock for the hosts has been the efforts of their almost-estranged countryman Gatland. The Lions coach was derided for his defensive mindedness and inflexibility ahead of the tour. He dispensed with that criticism in the first Test by choosing a surprisingly adventurous back line.

Gatland showed that he could be flexible when rearranging his line-up for the second test and utilising the Irish half-back pairing of Conor Murray and Jonathan Sexton, with Owen Farrell switched to the centre. The pack was also shaken up, with Maro Itoje given a starting berth and proving to be worth the investment.

That the Kiwis underestimated their countryman coach is hard to deny. He led the Lions to a series victory in Australia four years ago and that is no mean feat. Perhaps there is a disregard for northern hemisphere rugby which underrates his achievements with Connacht, Ireland, Wasps and Wales.

"I think we've played some good rugby," he said ahead of the third Test. "People expected us to come here and kick the leather off it, drive every single lineout and try and scrummage people to death. We haven't done that. We've played a good brand of rugby and people have been surprised and almost reluctant to give us credit for that. We've scored four tries and they've been four great tries. I'd like to think we'll leave here with some respect for the way we have played and that will be reflected on Saturday."

After two attritional Tests, the series now needs is an epic finale. If the Lions were to claim victory it would be their first series success in New Zealand since 1971. The Lions were so lost on their last visit in 2005 that the 3-0 reverse flattered them. It would be quite some achievement against a team considered one of the greatest of all time and who, having been stung by defeat, will raise their intensity to a level few could withstand.

Warren Gatland
Gatland has defied expectations by implementing an open brand of rugby. Getty Images