Sri Lanka pacers change their plan - and allow Namibia to change the mood at Kardinia Park

This wasn't how the script was meant to go. Through the first 15 overs of the opening match of the Men's T20 World Cup, you could have mistaken Geelong for the port city of Galle, minus the warm weather, as the Asia Cup champions looked every bit the cut above Namibia they were supposed to be.

Victoria has one of the biggest expatriate Sri Lankan communities in the world and thousands of them descended upon Kardinia Park to watch their side start their World Cup with a party at their home away from home.

The Papare band was playing. The Sri Lankan flags were flying. Sri Lankan colours were everywhere and the roars were all for one team as Namibia limped to 93 for 6 in the 15th over. The pace of Dushmantha Chameera and Pramod Madushan was too hot to handle on a tricky drop-in surface for a Namibia top order not accustomed to such speeds, bounce, and seam movement, even if the surface was slower than expected.

That was, until it wasn't. The band kept playing, but Sri Lanka's quicks stopped the chin music and Namibia stole the game from a near-impossible position to orchestrate one of the greatest upsets in T20 World Cup history.

For their part, Namibia were flawless from that point on and richly deserved a historic win. Jan Frylinck and JJ Smit produced the ninth-highest seventh-wicket stand in T20I history, and the third-highest in tournament history, to set an above-par target of 164. Namibia then bowled and fielded like a world-class team to strangle Sri Lanka's batters and bowl them out for 108.

As poor as the batting display was, it was abundantly clear where the game had gone wrong. Namibia had spent 12 months planning for the extra bounce and pace in Australia, practicing on synthetic and concrete pitches. But even though the Geelong drop-in was much slower than they had expected, Sri Lanka's quick men caused them all sorts of trouble with on-speed hard lengths in the first 15 overs. Jan Nicol Loftie-Eaton was the only Namibian top-order batter to strike a six in the first 15 overs, pulling Chameera over fine leg and cutting Chamika Karunaratne over point. But every other top-order player struggled.

That was until the last five overs when the quicks abandoned their plans completely and started bowling fuller with a mix of slower balls only to see Frylinck and Smit destroy them. The pair plundered 68 from the last five overs. Sri Lanka had only once conceded more in the death overs (17-20) of a T20 World Cup match than the 57 given away today.

Captain Dasun Shanaka was critical of his quicks in the aftermath.

"I think they tried too much," Shanaka said at the press conference. "I think if they stick to that hard length, wicket-to-wicket, like the Namibian bowlers did really, really well, it should have been different.

"I think we gave a lot of bad balls to hit boundaries."

Perhaps Sri Lanka's bowlers got sucked into bowling to the ground dimensions. Kardinia Park has short boundaries square and long boundaries straight, not dissimilar to Adelaide Oval, with some deep pockets at long-off and long-on, which sucked Sri Lanka's bowlers into erring fuller, something Maheesh Theekshana noted in the aftermath.

"I think we went with the dimensions of the ground but we didn't hold up the our line and lengths in the last 10 overs," Theekshana said. "We didn't execute our plans well.

"I think we went for the yorkers and we didn't execute with low full tosses and half volleys. I think that's where it went wrong."

Namibia's bowlers didn't make the same mistakes and Sri Lanka's batters folded under the pressure of the chase. Shanaka did not let his batters off the hook.

"We can't lose three wickets in the powerplay," Shanaka said. "It makes it very tough to chase down anything."

Sri Lanka weren't helped by the loss of Dilshan Madushanka for the tournament on match-eve. Binura Fernando has been called up as his replacement. Shanaka was asked about whether Lahiru Kumara could have played against Namibia to add some extra pace but he noted he did not want both Kumara and Chameera coming off long injury layoffs in the same game.

It now leaves Sri Lanka vulnerable. Drop one more game to either Netherlands or UAE and they could be out of the tournament altogether. They could also go through as the second qualifier from Group A, which would put them on the same side of the draw as India and Pakistan in the Super 12s.

But none of that was of any concern to Shanaka.

"It's the first game," Shanaka said. "But the way we played is the worry."

The Papare band kept playing and the fans kept cheering throughout the doomed chase and their support will remain boisterous and unwavering, particularly in Victoria.

But it was jarring to hear them fall silent for the first time as the 10th wicket fell and a small pocket of Namibia supporters drowned them out as reality sunk in.

The Asia Cup champions and a fancied in-form dark horse for the World Cup had the script flipped on them by Namibia.