YORKSHIRE superstar Joe Root was relieved to turn his own words into actions after kicking off 2021 with a classy century for England against Sri Lanka in Galle.

Root has not hidden from the fact that this year could be a defining one for his captaincy, with home and away series against India and an Ashes tour Down Under all hovering into view, and he called on the team to start with a bang against Sri Lanka.

The bowlers did their part by rolling over the hosts for just 135 on day one, a total Root overhauled all on his own as he cruised to 168 not out today.

That represented over half of the team's stumps total, 320-4, and provided the bulk of a towering 185-run lead.

Having not reached three figures since December 2019, the wait for an 18th Test hundred had gone on long enough and the drought ended in a style as he defended strictly, swept with authority and compiled England's record score on the island with a disarming ease.

"I'm extremely pleased, I did a lot of talking before the game and ahead of this year I thought it was really important to go out there and do it myself," he said.

"It felt like a long time coming and now I've got to build on this, really make it count. I want to make it as big as possible and drive this first innings lead as high as we can.

"When I was a little bit younger on previous trips I might have tried to play too many shots to the same ball. One thing I was really pleased with today was my shot selection.

"I felt I got a really good combination of defence and attack. Being a bit more ruthless, a bit more stubborn and trusting my defence a little bit more at times has certainly paid off this week."

Root's conversion rate from 50 to 100 has often dogged him as a weakness - he now has the same number of centuries as Michael Vaughan but leads his predecessor by 31 half-centuries - but even taking lunch on 99 not out did not throw him off here.

It is a problem many players across the world would love to experience and one Root is trying not to indulge any more.

"For the last year, two years, I've over thought it massively. I've tried to get away from that," he said.

"I've made too big a deal of it in my own mind, hyped it up, and probably because of that it's been to my detriment.

"Generally when I do get to hundred I make it really count so tomorrow I'm trying to make that another really big one and drive the game forward.

"We want to put them under pressure and bat just once."

Root shared a fourth-wicket stand of 173 with Dan Lawrence, who scored a fine 73 on debut.

Lawrence and Root's fellow Yorkshireman Jonny Bairstow were the only two players to be dismissed all day.

The Bradfordian failed to add to his overnight score of 47, caught low down at gully off spinner Lasith Embuldeniya.