Australia may have romped to a 91-run win over Zimbabwe in their opening World Cup Group A clash, but captain Ricky Ponting admitted his side were made to work hard for the result.

Chasing 263 for the win, Zimbabwe crumbled in the face of Australia's pace attack as Mitchell Johnson and Shaun Tait picked up four and two wickets, respectively.

Spinner Jason Krejza also chipped in with two of his own to help skittle their opponents out for 171 and secure a 30th successive World Cup win.

Australia had earlier endured testing spin conditions for large parts of their innings - with Zimbabwe introducing spin in only the second over - but Shane Watson's 79 and some late hitting by Michael Clarke (58 not out) racked up a respectable total.

And Ponting revealed the defending champions had decided to adopt a patient approach to sub-continental pitch conditions - a tactic that enabled them to score 90 runs off the last 10 overs.

"I thought Zimbabwe bowled particularly well on a really slow wicket," Ponting said.

"It was tough for us to get any pace on the ball. Then their spinners came on and they bowled 38 or 39 overs of spin today.

"We just kept ourselves in the game, got ourselves a decent total and we knew that if we bowled well we would have enough runs "That'll be pretty much our philosophy throughout the tournament. Around the time of the ball change, you need to have wickets in hand through the middle overs.

"I thought the way we approached it was about getting through those tough times. We could have got a few more runs but, overall, a pretty good start."

With their top half having collapsed for just 88, Zimbabwe skipper Elton Chigumbura recognised it as a game of two halves for his side, saying: "I thought we had restricted them to a total that we wanted to chase.

"I was very happy with the bowling department and, overall, our bowling and fielding were superb.

"But we just have to work on our batting. We didn't put enough runs on the board. It was a good wicket to bat on but we just lost too many wickets up front."