JOE Root will cherish his 15th Test century as one of his very best, but only if England's bowlers finish the job and seal a series win over Sri Lanka.

Root's 124 on day three in Kandy was a quite brilliant innings, both in the context of a finely-balanced second Test and on a Pallekele pitch offering consistent turn for a quartet of rotating spinners.

It was also the first time the England captain had made a second-innings hundred away from home, with his previous overseas efforts in Grenada, Johannesburg and Rajkot all setting up the game rather than defining its end state.

There were no second chances here, without Root's ebullient 146-ball effort England would never have touched the heights of 324-9, enough for a stiff lead of 278 in challenging conditions.

Root has never experienced the mixed emotions of reaching three figures and losing the same Test - winning 11 times and drawing three - and does not want to break the habit now.

"It was very pleasing to make a big contribution on that pitch. It would be a very special one if we go on to win the game and win the series," he said.

"I certainly enjoyed myself today, it was really good fun and that's what it should be. You shouldn't feel like the pressure is too much for you; enjoy the occasion and make the most of the opportunity in front of you.

"At times attack is the best form of defence."

Root took risks and sparred with the bowlers early in his innings before settling after lunch and cruising towards three figures with increasingly confident footwork and ball-striking.

"There were a few filthy hacks in there at times," he joked.

"To start with I felt a bit all over the place to be honest, a bit hectic. I was a bit like a reverse swan - I felt quite calm underneath but I was flapping on the outside."

Root may have been the standout but his innings was preceded and followed by similarly strident knocks from Rory Burns (59) and Ben Foakes (51not out), both men winning only their second caps at this level.

"It was really pleasing to see inexperienced guys, as Test cricketers, really set the benchmark for the rest of the group," added Root, in a nod to the Surrey pair.

"I think the temptation with a deficit like the one we had (46 runs on the first innings) is to play within your shell and be a bit insular but the guys went out and set the tone.

"It suits the group, the players we have and you have to play to strengths. Especially on difficult surfaces when there's extreme spin like here. You have to try to put pressure back on the opposition."

Root has repeatedly called for brave decision-making from his side this winter and was more than happy with the compulsive desire for conventional and reverse sweeps which brought a welter of English runs but also directly accounted for their first seven wickets.

"We got the balance right," he asserted, having himself cashed in heartily with the stroke before perishing lbw to it.

"We spoke about playing to our strengths individually and from my point of view it was almost a safer shot than playing the forward defensive.

"With the amount the ball was turning there's a lot of risk involved in that. The guys have not been shy of experimenting."