What the series might come down to is X-factor. The respective forward packs will no doubt hold their own. The kicking duel and aerial battle will most likely come out about even and the difference, as it so often is, will be the ability to create something out of nothing.
And no one in the world game can do that as well as Barrett. No one right now has that same trust in their skills and confidence to try the impossible.
No one has the same blistering pace that he does - not anyone playing in such a central decision-making capacity, anyway.
The Blues might toss and turn for a while yet about how they let the game slip in the last 10 minutes, but what were they to do when Barrett dinked the ball over their defensive line with the outside of his right boot, scorched through to collect it and then two phases later made the cleanout to ensure Mark Abbott scored?
What could they have done differently to have stopped Barrett firing through their defence in the first half to set up the first try for Ngani Laumape? The defenders were in the right place, Barrett was just too quick, too clever with his angle and the hole, that wasn't there, opened up.
Even Barrett's own try where he pounced on a dropped ball wasn't as lucky as it seemed. He made his own luck because he had the pace to get to the ball first.
"We talked about that we had to win those big moments and he single handedly does that," said Hurricanes coach Chris Boyd. "And he is regularly responsible for seven or 14 points for us each week."
The Lions, undoubtedly selecting from one of the best crop of players the Northern Hemisphere has harvested in ages, don't have anyone quite like Barrett in their midst.
They have Johnny Sexton, who has a great range of skills and a temperament to use them, but he doesn't pose the same danger as Barrett.
The Lions also have George Ford, Owen Farrell and Elliot Daly, but none present that same challenge to defend or contain.
"I just remember him running around with his brothers when I was playing with his dad," said Umaga of Barrett.
"I knew his dad was very skilless so obviously it all came from his mum. He's just grown. It's everything; his ability to bring the ball back from deep, his vision, his confidence. Everyone has talked about the areas he's worked on with his defence and when you think about the ways to curb 10s like him, that's when you needed his dad who was very good at curbing 10s back in the day.
"That's part of the skill he's given his son because he is tough, relentless and always competing right till the end. That last try they got he was the one that cleaned out around the corner that opened the space. So 10s are different now."
