Before Rangana Herath's 19th over of the day, Sri Lanka were drifting towards trouble. The pitch had begun to bite, and Bangladesh were edging ahead in the third innings with not much fear, for not much menace defied them.
In two brutal balls, Herath reeled in the upper hand for his side again. Jahurul Islam, having ground a gutsy 48, stepped down the track to lay down his terms for Herath's spell, but a dipping Herath ripper wouldn't have it. Chandimal collected and stumped the batsman well out of his crease. Mahmudullah arrived, received a flatter one that gripped and felled off stump, and was back in the dressing room within two minutes. Later in his spell, Mominul Haque was dropped at mid-on, and Mushfiqur Rahim shelled at slip. Called in to make a breakthrough, Herath served up Bangladesh's innings on a plate. The chance to shut the visitors out may have been missed, but Sri Lanka will sleep easier with only six more to get on day four.
That spell, though, in its impact, raises a series of worrying questions. What if Herath was not playing? What if he had a bad Test? He took five wickets on the first day, and now has three of four on the third. Would Bangladesh have made 100 more in their first dig? 150 maybe? Probably. Would they be cruising towards a big lead in the second innings, as the pitch disintegrates? Also likely. Are Sri Lanka, in their home conditions, a worse Test team than Bangladesh, save for Herath?
He has effectively assumed Muttiah Muralitharan's mantle, only his body was shaped in a mortal's mould, and he will perhaps never be a great, given he is on the brink of 35. Without Murali, Sri Lanka have won 11 Tests and lost 39. With him, they triumphed 54 times and were beaten in 41. Herath, who has taken five wicket-hauls in three of the four victories since Murali's retirement, has not only inherited Murali's responsibility, but his team-mate's frailties as well. The team has slipped from one one-man-show to another.
At present, Herath is at once sledgehammer and workhorse. When his side grows desperate for a breakthrough, Sri Lanka look to him. When an opponent is mowing bowlers down, Herath must be on hand to tamp the blaze. A long, tight spell, a sneaky wicket before day's end, new ball, old ball, greentop, dustbowl, Herath is the man. The only man. How tiring it must be, though his cricket never seems careworn.
On Sri Lanka's recent walloping in Australia, not only did the other bowlers fail to contribute with notable hauls, they undid Herath's fine work at one end with waywardness at the other. Worse, they spilled several chances that he created, as they have done again in Colombo. Besting Test batsmen is not a cakewalk for Herath as it often was for Murali. He grafts for wickets - spends eons setting them up. A dropped chance often means that a lengthy process must begin again. How cruel, for a man who gives far beyond his own ability in the field.
There were encouraging patches for Herath's support crew on day three, however. Shaminda Eranga had been one of those whose indiscipline set Sri Lanka back in Australia, but showed commitment to line, length and pace throughout his spells at the Premadasa, and removed Tamim Iqbal. Eranga still lacks the movement, in the air and off the pitch, to be a major Test threat, but Sri Lanka's pace attack must walk before it can run, and control at least, is a step on that journey.
"Eranga's developing quite well," Kumar Sangakkara said after stumps. "It's just a case of day-in-day-out that you have a specific plan to work towards in practice and even in a match. Even if you take the most successful bowlers, not a lot of them are extraordinary bowlers. You've had a few like Murali who was a freakish X-factor, or you had Shane Warne, who was probably one of the unique bowlers that you get very rarely. But if you take the rest of the fast bowlers - Glenn McGrath, Wasim Akram, all of them had one thing in common. They were very accurate and they managed to put the ball in the right place. Other than that there was no magic in it.
"For Eranga and all other fast bowlers, it's just a case of understanding that and putting that ball consistently in a place that challenges batsmen and keeps making him play. You can't try and bowl magic balls, you can't try and get batsmen out. It's just a case of bowling to a plan and if there's swing, letting the ball swing and if there's seam, letting the ball seam. Your job is to just hit that one spot."
After his five-wickets on day one, Herath said he hoped to have 50 wickets in Galle before he retired. He is only two short, but Sri Lanka's next home Test there is not until 2015, when Herath will be 37. If he waits that long to call it a day, he may just buy his team-mates enough time to learn to hunt as a pack, and build, with heart, upon each other's efforts. But, maybe not. Maybe another must emerge, to tread the lonely path Herath has trekked so tirelessly.

Andrew Fidel Fernando is ESPNcricinfo's Sri Lanka correspondent. He tweets here