Only days ago, Joe Root didn't rate pink-ball cricket. But now it's helped him change his legacy forever

As Joe Root pushed into the nervous 90s at the Gabba, Nasser Hussain could barely sit still in the press box.

The voice of reason in English cricket punditry, Hussain looked tense.

The former captain stepped outside to soak in the atmosphere at one stage before returning inside. Then there was the elbows on knees with a nervous look forward.

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Hands in head when Root almost had a mix-up with Will Jacks on 96.

Then came Scott Boland's over. Alex Carey up to the stumps.

It felt like the whole of England were nervous.

Ball one slapped into the pad and inside edge but fell safely.

"He's become a bit tentative here," Kerry O'Keeffe said on Fox Cricket.

Next delivery was a bouncer and called a wide.

Legal ball two was a mistimed on-drive, along the ground, straight to the fielder.

Then that leg glance for a boundary came and it was the calm Hussain again. A slight smile and clap

"I very rarely get nervous watching present cricket, we've been through that all in our careers," he said on Sky Sports Cricket podcast.

"But I did get nervous when he got to 80-90, he went into the 90s pretty quickly.

"He's got 39 Test hundreds before today and none of those I was worried about but I was worried about this one simply because of its significance, because of the hype, because of the chat."

The celebration of Root was very much him. Humble and calm.

From the crowd, it was a mix of cheers and boos as England fans celebrated one of the nation's greats while Aussies realised they no longer have a stick to hit him with.

Root's day one at the Gabba was career defining and a legacy moment.

It was also rather ironic considering Root had said in the lead up that The Ashes shouldn't have a day-night Test.

Mitch Starc saw the funny side of it after play.

"I hope you guys (the media) give him some stick, you've been nailing me about 14 pink-ball Tests that I still don't like it and he was whinging about a pink ball Test and scored a hundred," he smiled.

While it was a moment to savour for Root with his first century in Australia, what would've mattered most was the situation.

Without his runs, England would've been embarrassed again with the bat.

He watched as Harry Brook played a rash shot and then rightfully sent back Ben Stokes before his skipper was run out.

At 4-176, then 5-210 before 6-211, England needed its best to stand up. And that he did.

"We were chuffed for him ... I think he was less nervous than us," Zak Crawley said after play.

"He was so humble, he's not trying to make too much of a deal of it but I'm sure inside he's pretty delighted."

Now the monkey's of the back, the scary thought for Australia is what Root can do from here.

We're only at day one, and Root's delivered the entrée.

What's the main course going to offer?

We don't know, but that's why we love Test cricket.

Because it delivers time and time again and day one belonged to Joe Root.