There is nothing in the world more like Tillakaratne Dilshan than the shot he brought to cricket in 2009. Like the man, the stroke treads the line between daring and embarrassment. If he wears the 'Dilscoop' on the helmet, nothing looks so foolish. If he connects, he sends stadiums into raptures. It's a shot that has the feel of a heist. Modern captains have never put men behind their wicketkeeper. They probably never will. By hitting to this part of the ground, Dilshan is almost cheating.

In some part of his mind, though, this roguish, dashing 2009 version of himself still exists, because Dilshan still talks a big game. "If you compare my performance with the others," he said recently, "I have a better batting average in ODI cricket." The "others" in that sentence are Kumar Sangakkara and Mahela Jayawardene, and the statement is not quite true; Sangakkara outstrips his average year-on-year.

But what is important is that Dilshan himself believes it. The facts about Dilshan's batting are not nearly so important to his team as the bluster that underpins him. In 2011, Dilshan became captain and ditched the designer beard and bad-boy gold chains, only to enter some of the leanest months of his career. In 2014, he launched a clothing line, the advertisements for which featured himself, shirtless, in a quarry, lying suggestively on a pile of jeans and abseiling on a rock face. That year, he hit more than a thousand runs.

But his head is perhaps the only place where bad-boy Dilshan still exists, because the batsman who was reformed in 2009, has now been refined again in the least thrilling fashion imaginable. Sometime in the last two years, and perhaps unbeknown even to himself, Dilshan has become a steady hand. He's an engine-room player, when he used to be a sports car with switchblade doors and a spoiler.

Much of his 161 not out off 146 balls against Bangladesh was everything an ageing one-day opener should produce. The beginning was not quite sedate, but it was measured. While Lahiru Thirimanne, no attacking batsman by nature, was sliding out of his crease to the quicks and aiming big blows to the legside, Dilshan pinned himself in the crease. Only the half-volleys and half-trackers went to the fence. Of Sri Lanka's first 50 runs, Dilshan had scored 15 (though that was partly due to having had less of the strike as well).

The Dilshan of the past outmatched partners shot for shot. His feet flitted about where now they plod. Sri Lanka were not exactly motoring after 18 overs, having scored at 4.61 an over, but Dilshan was startlingly unambitious as Taskin Ahmed delivered a maiden to him in the 19th. No booming drives came after the first few dot balls. There was no self-chastisement when he failed to pierce the field.

His pace quickened soon after, but Sangakkara made better use of Bangladesh's wayward bowling. Not so long ago, Sangakkara was the more reticent of the two, while Dilshan flashed away. Only at the death did Dilshan find the top gear Sangakkara had been in since he arrived at the crease.

"Just after taking a start, I want to bat as long as possible," Dilshan said. "The thing is I know that in the last 10 overs, I can catch up easily, especially with the four fielders outside. I started very slowly, but caught up with Kumar in the last five overs. In the last 10, we took more than 120 runs. We know if we keep wickets in hand, we can score more than 100 the last 10. I think that's why we got 300 plus today."

All through the recent series, those halting starts have been fruitful for Dilshan. This knock was his highest score, and the record at a World Cup for Sri Lanka, but he also has four tons in his last 10 innings. Among those outings is an 81 and a 44. For so long, Dilshan was a flagbearer for Sri Lanka's attacking tradition at the top of the order but, in his new avatar, he is almost an '80s throwback.

All three Sri Lanka seniors have hit hundreds at this World Cup now, suggesting the batting experience will begin to pay off in matches to come, though the bowling remains wayward. It will almost certainly be Dilshan's last World Cup - his energy and optimism notwithstanding - in addition to Sangakkara and Jayawardene's, and he is playing like a man who knows that.

Dilshan is taking stock of options. He's playing percentage cricket. He's mature. He's 38. He's a little boring. And he's probably never been better.

Andrew Fidel Fernando is ESPNcricinfo's Sri Lanka correspondent. @andrewffernando