The Sri Lanka number three made an unbeaten 178 — the third highest individual score in a women's ODI — in a seemingly competitive total of 257-9. Atapattu's innings featured 22 fours and six sixes.
But poor fielding and catching meant Sri Lanka's spin-dominated attack rarely looked like defending such a score, with Lanning making 152 not out — her 11th ODI century a women’s record at this level.
Lanning ended the match in style, hitting a six to bring up her 150 and seal victory for Australia with nearly six overs to spare.
Sana Mir ready for Women’s World Cup challenge
It was their second dominant success of the tournament, after an opening eight-wicket win over the West Indies.
But Atapattu received the player of the match award and an admiring Lanning said: "Once she got going, it was hard to stop her. We couldn't stop her in the end, anyway. We know she likes to hit the ball hard and straight. We tried a whole lot of plans but none of that worked — a very special innings."
Lanning knew Australia needed something special to chase down the total. "In the innings break, I said we need someone to get a big score. It was good that I managed to do that."
Australia to start as favourites for Women's World Cup
Sri Lanka captain Inoka Ranaweera had mixed emotions. "I think we need to build partnerships and play in the middle, so I am disappointed. I am proud of Chamari, I am very happy,” she said. “For our next game against England, we will look to make fewer mistakes."
Meanwhile, India, who stunned hosts England with a 35-run victory, also made it two wins from two as they overpowered the West Indies by seven wickets at Taunton.
Opener Smriti Mandhana got to three figures with an unbeaten 106 following her 90 against England.
She added 108 runs for the third wicket with captain Mithali Raj (46) after India were in trouble at 33-2 chasing a modest 184.
India kick off Women’s World Cup with statement win
"Smriti played well for her hundred, it was a crucial innings she played," said Mithali.
India's spinners made life so tough for the West Indies that even the usually dynamic Deandra Dottin — holder of the fastest century in women's T20Is — could manage a mere seven off 48 balls.
The West Indies slumped to 91-6 before some late-order hitting boosted the total.
"We didn't get the batting right in the middle," admitted West Indies captain Stafanie Taylor. "We have the batters to do it but I think it's up to the batters to take more responsibility in their actions," he said.
All the eight teams involved play each other once, with the top four contesting the semi-finals.
The final takes place at Lord's on July 23.
COMMENTS
Comments are moderated and generally will be posted if they are on-topic and not abusive.
For more information, please see our Comments FAQ