World Cup, Port Elizabeth - Starts 0800 GMT Tuesday
It was only 10 days ago that Australia kicked off the Super Six phase of the World Cup with an emphatic 96-run win over Sri Lanka.
On that form, the holders look a certainty to progress to next weekend's final in Johannesburg.
But cricket, as has been said many times, is a funny game.
Australia have won 22 of their last 24 one-day matches but on the two occasions when things did not go to plan, Sri Lanka were the team to upset the odds.
Muttiah Muralitharan took 3-26 as the Aussies were bowled out for just 162 in last September's ICC Champions Trophy semi-final and they eased home by seven wickets with 10 overs to spare.
Sanath Jayasuriya (122) and Marvan Atapattu (101) were the match-winners two months ago in Sydney as an opening stand of 237 paved the way to a total of 343-5, with Australia falling 79 runs short of their target.
Those three players, along with leading wicket-taker Chaminda Vaas, are likely to be the key figures again if Sri Lanka are to reach the final for the first time since their 1996 triumph.
We're now at the business end of the tournament
Sri Lankan coach Dav Whatmore
They also have an advantage in that Dav Whatmore understands the Australian way of doing things perhaps better than any other coach - hardly surprising as he played seven Tests for them in the 1970s.
"We play a similar brand of cricket to theirs - aggressive, in your face cricket. That's why we've been able to beat Australia (in the past"," Whatmore commented.
Sri Lanka will also take heart from Australia's problems in their two previous games at Port Elizabeth against England and New Zealand, both of which they would have lost but for the batting of Michael Bevan and Andy Bichel.
Bevan returns to the Australian team, having been rested for the Super Six match against Kenya, but the loss of Damien Martyn with a broken finger is a potentially significant setback.
Groundstaff at St George's Park believe this pitch will have more pace and bounce and if their predictions come true, Australia plan to make the most of it.
Jayasuriya was roughed up paceman Brett Lee in their last match at Centurion, suffering a cracked thumb and bruised arm.
Both he, and opening partner Atapattu, can expect more of the same.
"Intent and intimidate - those are words that were used at the start of the tournament. It will be just a progression of what we started," skipper Ricky Ponting commented.
"We just need to keep performing at a higher level and if we keep doing it, I can't see any reason why we can't take it (the trophy) home."
Sri Lanka's main dilemma concerns whether to keep faith with batsman Avishka Gunawardene, who made 41 against Zimbabwe, or recall the hugely talented, but wretchedly out of form Mahela Jayawardene.
Whoever plays, they are aware of the need to avoid early lapses.
"They want to run down the opposition all the time, right from the start. If we can dominate the first hour of the game, it will be very important," said captain Jayasuriya.
Australia (from): Ricky Ponting (captain), Adam Gilchrist, Michael Bevan, Andy Bichel, Matthew Hayden, Brad Hogg,
Brett Lee, Darren Lehmann, Jimmy Maher, Glenn McGrath, Andrew Symonds, Nathan Hauritz, Ian Harvey, Nathan Bracken.
Sri Lanka (from): Sanath Jayasuriya (captain), Marvan Atapattu, Mahela Jayawardene, Kumar Sangakkara, Aravinda De Silva, Russel Arnold, Jehan Mubarak, Avishka Gunawardena, Hashan Tillakaratne, Muttiah Muralitharan, Chaminda Vaas, Dilhara
Fernando, Pulasthi Gunaratne, Prabath Nissanka.