A seven-wicket win, an Australian World Cup-record opening partnership, a 34th consecutive World Cup match without a loss. That all sounds pretty good if you're an Australian fan. But if Australia play like they did against Canada when the knockout stage begins next week, they won't be lifting the World Cup.

And Ricky Ponting knows it. When he collided with Steven Smith as they both positioned themselves under a skied ball in the 42nd over of Canada's innings, he held the catch but dropped his bundle. Ponting hurled the ball into the turf and walked away from the group, crouching at mid-off while his team-mates were standing beside the pitch, celebrating the wicket.

The captain had called for the catch and felt that Smith hadn't listened, and his team-mates hadn't called at Smith to stop. It wasn't a good look for Ponting to turn his back on his young colleague, but he had cause to be frustrated. His men were making errors and for the second time in four days an Associate nation was making them look average. On Sunday against Kenya, they could blame rust, after a fortnight off. On Wednesday, they were just sloppy.

And against Pakistan on Saturday, and potentially the likes of India or South Africa next week, that won't cut it. Impressive as Hiral Patel was, he is no Virender Sehwag, and Henry Osinde is no Dale Steyn. Yet these men, just like Collins Obuya and Nehemiah Odhiambo at the weekend, found weaknesses in Ponting's outfit, including the fact that later in the evening the captain was out hooking yet again, this time to Osinde.

Fortunately for Shane Watson and Brad Haddin, luck was on their side. Watson should have been caught in Harvir Baidwan's first over when he skied a chance to mid-on, and Haddin nearly played on to Osinde and then survived a perfect lbw shout that Canada should have reviewed. The openers were loose and lazy early, but they were wonderful later, and that is the one great positive Australia can take.

In the field, they lacked polish. In the lead-up to the tournament, the former swing bowler Damien Fleming said Australia could be bowling teams out for 50 or chasing 500. And when the Canadian top order slapped and sliced their way to the fastest team half-century of the World Cup, getting there in 4.4 overs, it seemed that Fleming's throwaway line wasn't so far from the truth.

That's the risk of playing Shaun Tait, Brett Lee and Mitchell Johnson. As Canada showed, their speed can be used against them. Lee ended up with four wickets, but in his new-ball spell varied between being too full with no swing, and too short and inaccurate. Against Patel and John Davison it was costly enough, but a class opener like Sehwag or Chris Gayle could have massacred that bowling.

The Australians chose not to give John Hastings a game against Canada, but Watson demonstrated why variety in the seam attack is valuable. As soon as Watson came on the runs dried up. He was accurate, consistent and took the pace off the ball - which cost Patel his wicket when he went for an upper cut that landed in third man's hands.

But Watson himself had moments he'd rather forget, like when he spilled a catch at slip off Karl Whatham's edge. There were other mistakes with the ball and in the field: Michael Hussey grassed a hard chance above his head in the first over and then gave away overthrows with an unnecessary throw at the stumps, while Johnson, as he often does, bowled a couple of balls that barely made it on to Hawk-Eye's pitch map.

It all added up to a mixed-bag of a performance, though the way the Canadian lower order struggled and Australia's openers gradually found their touch, it turned Australia's way. Ponting knows that against Pakistan, on Saturday, they need to prove they can beat a quality side.

"Against better teams and deeper batting orders, we have to make sure we don't let teams get off to that sort of start," Ponting said. "If you look at someone like Sehwag, he plays a pretty similar way to what [Patel] played today, and if we happen to let him get off to a start like that in a big game, it's going to be a whole lot harder to peg them back. We've got some work to do, but I don't think we're that far away. We'll get a better indication when we take on a good team in a couple of days' time."

At least when Australia's players walked off after they bowled Canada out, Ponting gave Smith a pat on the back. All's well that ends well, but if they don't lift, their World Cup will be ending well before they want it to finish.