How long can he keep going? No, really. Rangana Herath is 40 in five weeks. By that age, Wasim Akram - the man he has just passed to become the most-successful left armer - had been retired for three years. Daniel Vettori, next-best on that list, is in fact 10 months younger than Herath and had anyway been a tied-together collection of limbs towards the end of his career.
Herath has been complaining of bad knees since the Triassic. Every series he sours his face as he dwells on ailments. Yet, on he rolls - the hair a little greyer, but the wickets still as bountiful - like he has been looting other left-arm spinners for parts.
It has been suggested that he is defying age, but can we really accept that? Tillakaratne Dilshan defied age - his fielding as electric at 40 as it was 10 years prior. Kumar Sangakkara defied age, revolutionising his own limited-overs game, collecting fandangled new shots until the date of his retirement. Herath, meanwhile, has waddled around the field for eight years, forever appearing as if he is being weighed down very, very heavily by mortality. His game, actually, has devolved a little. He had been the modern-day inventor of the carrom ball in the nineties, but now, that is a delivery he deploys less and less.
To watch Herath in this latest phase of his career is to behold a player who rather than waging battle against father time, has embraced him, and maybe cut a deal. He is an infrequent netter; almost never will he turn up for training before the day of the game. On the field, he has honed his skill for staying hidden, rarely called upon to make a long chase into the outfield or attempt a diving stop. At the start of each of his overs, he turns up at the bowling crease like he has just popped out of the earth. The moment his cap is retrieved, the field swallows him up again.
None of this is to say he is unfit, because as one Sri Lanka trainer pointed out, Herath is in fact the fittest player in the side in one sense: he is almost always available to do his job. Of Sri Lanka's 35 Tests since 2015, he has played all but three. Often he is workhorse as well as spearhead, keeping batsmen in check through long, difficult spells while teammates sometimes release the pressure at the other end. When he reaps a big harvest, such as his 6 for 43 on the fifth day at Abu Dhabi last year, you almost forget that he had ploughed that soil for 40 overs in the first innings. His is a triumph of longevity. No sane person will contend he is a better bowler than Wasim was, but though Herath is short on genius, of collapses sparked and matches won, he has plenty of.
"As a left-arm spinner or as a left-arm bowler, taking 415 Test wickets, passing Wasim Akram... of course, to be honest it is kind of a big achievement," Herath said after the Mirpur Test. He has clearly tasted too much success in his career to feign modesty now. Outshone, if only slightly, by a 24-year-old debutant on Saturday, Herath's enduring presence in the side has value beyond the wickets he himself takes.
"In this team we have a mix of juniors and seniors, as well as in-between players," Herath said. "So I have an opportunity to pass on my experience, and that is what I do."
To predict when Herath will retire has become a futile exercise. On these very pages, it was suggested that he would step down - surely - in 2016. Having proven selectors, oppositions and even teammates wrong through the course of his career, we were among the lower-profile casualties. Suggesting that Herath is past his best is now one of cricket's most recurrent stupidities, so many times has he flaunted another match-winning spell in naysaying faces. In this most-recent four-wicket haul, one batsman was lavishly outsmarted the very delivery after he had hit Herath for six, and another's thoughts were so scrambled that his decision to come down the pitch was made almost after the ball had already passed him.
Is he a capital-g Great? Maybe. I don't know. Does it matter? The point is, here is a bowler who was always a little out of shape. Now he is also old. And yet, as he surpasses some of the game's most exalted figures and plonks himself in the pantheon, this chubby, ancient guy can still embarrass your batsmen.

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