Australia 91 Japan 3: Wallabies win by a landslide but lose wing Gerrard

Australia's World Cup campaign began with a record score and a cruel blow. The winger Mark Gerrard is out of the tournament after injuring his left knee in a 13-try demolition of Japan.

A scan on Saturday revealed a ruptured medial ligament which will put Gerrard out for six to eight weeks. The 25-year-old spent barely a minute on the pitch as a replacement for the captain Stirling Mortlock, whose seven conversions and two penalties earned a 20-point tally.

"It's disappointing, especially at this point of the tournament," said Gerrard. "I pretty much knew straight away, when I heard it click, what would happen after that." John Connolly is expected to draft in Cameron Shepherd. Another winger, Adam Ashley-Cooper, suffered a bruised big toe and is doubtful for Saturday's match against Wales in Cardiff.

Despite the scoreline, the Japanese were not completely humiliated. They restricted the Wallabies to three tries in the first half, but when the flanker Rocky Elsom completed his hat-trick 50 seconds into the second half, that was that.

The debutant Berrick Barnes, a replacement for Stephen Larkham, scored with his second touch and added another. Chris Latham scored two, as did the replacement winger Drew Mitchell.

Japan counter-attacked early on, the right winger Tomoki Kitagawa combining with Hirotoki Onozawa in a move that caught the Wallabies napping. The only score for the Japanese, a penalty, came from the boot of Kosei Ono. The captain, Takamichi Sasaki, injured a knee, making him a doubt for Wednesday's game against Fiji in Toulouse.

Australia: C Latham; A Ashley-Cooper (D Mitchell, 59), S Mortlock (capt; M Gerrard, 69-71), M Giteau, L Tuqiri; S Larkham (B Barnes, 55), G Gregan; M Dunning (G Shepherdson, 68), S Moore (A Freier, 68), A Baxter (G Shepherdson, 51-68), N Sharpe (H McMeniman, 51), D Vickerman, R Elsom, G Smith, W Palu (S Hoiles, 68).

Japan: T Kusumi; T Kitagawa, K Taira, N Oto, H Onozawa; K Ono, Y Yatomi; M Yamamoto, T Inokuchi, R Yamamura, T Kumagae, L Vatuvei, T Watanabe (H Makiri, 9-12), T Sasaki (capt; H Makiri, 49), H Kiso.

Referee: A Lewis (Ireland).