Two quicks capable of bowling faster than 145kph, one allrounder who gets up into the high 130s range, a spanking new mystery spinner who is yet to be decoded, and a world No. 2 legspinner with a killer googly. These are Sri Lanka's frontline bowling stocks for this World Cup. They are so good, says coach Mickey Arthur, they could be "almost the ideal attack".

They were excellent against a Namibia side that Sri Lanka were expected to overpower, with Maheesh Theekshana (the mystery spinner) picking up three wickets, and Lahiru Kumara producing good overs at each stage of the innings. But Ireland, a more formidable outfit, will be a step up.

Still, Arthur is excited, particularly by Dushmantha Chameera (who bowled one delivery at 149kph on Monday, and whose bouncers can be truly nasty) bowling in tandem with Kumara, who also comfortably breached 145kph. This may be the lowest-rated Sri Lanka outfit ever to arrive at a T20 World Cup. But they've also never had a quicker attack.

"For us to have two bowlers of genuine quality bowling at 145kph - that makes a massive difference," Arthur said. "We know that any team doesn't like facing them. They're genuine wicket-takers. Their skills have got better and better over the last couple of months. We're really happy having them attack for us.

"Dushmantha Chameera has gone to another level. He's now genuinely world-class. To have those bowlers in our line-up gives us a good balance. Chamika [Karunaratne] brings a little bit of swing. And we've got our two spinners. It's almost the ideal attack, if you like."

They will be tested by an Ireland batting order that seems to be finding its feet, but if they bowl second in Wednesday's match, they will also have to contend with the dew. Across both World Cup venues so far, sides bowling second have struggled to keep the ball dry. Sri Lanka bowled first against Namibia for this very reason. But they are prepared if the toss goes the other way against Ireland, Arthur said.

"We came out the night before the Namibia match and checked the amount of dew, and there was a fair amount. I don't think it's impossible to bowl if we have to bowl second. We've prepared that way - using wet balls, etc. We'll be ready. Once the wicket cools down and gets a little bit of moisture on it, it just tends to come on a little bit nicer as well."

Sri Lanka will stick with the same top three, according to Arthur. They did not fire against Namibia, with each of Kusal Perera, Dinesh Chandimal, and Pathum Nissanka all getting out cheaply. While Perera has produced some good T20 performances, Chandimal and Nissanka are not highly rated hitters - their gifts favouring the Test format. Arthur sees no reason to change, though, with Perera dropping back into the top three following his latest injury layoff.

"I'm pretty confident with Kusal Perera back at the top of the order now," Arthur said. "He's a world-class player, so to have him back there gives us a lot more solidity. I'm pretty sure he's going to fire for us soon.

"Pathum Nissanka is a work in progress. I've said numerous times that he's the one young Sri Lanka batsman that I've seen in my time that is going to go on and genuinely become a world-class player for Sri Lanka. We'll keep going with Pathum because we're investing in him. That No. 3 position has been an Achilles heel for us, ever since we lost Kusal Mendis, Danushka Gunathilaka and Niroshan Dickwella, we've battled to find the right balance in our top five. I'm comfortable we can find that balance if we can nail down that No. 3 position."

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