Van der Merwe carries it forward. (Getty Images)

By Simon Stone, PA Sport, Sydney

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The abysmal Sydney weather proved a more difficult obstacle to overcome than Namibia for Ireland as they continue their march towards a World Cup quarter-final spot.

Eddie O'Sullivan's men had victory wrapped up inside 14 minutes, by which time they had crossed for the first three of their 10 tries.

But although they eventually posted their best World Cup win, Ireland would have gone much closer to hitting their international best 83-3 romp over the United States four years ago had it not been for the torrential rain which fell constantly at Aussie Stadium from an hour before kick-off.

With handling so difficult and opponents so weak, O'Sullivan might struggle to find the vital selection pointers ahead of next Sunday's crucial clash with Argentina in Adelaide which will determine whether his side advance to the last eight.

However, back-row duo Alan Quinlan and Eric Miller will not have done themselves any harm with two tries apiece and popular fly-half Ronan O'Gara added seven conversions to an excellent open-field kicking game.

But, as impressive as the win was, it may yet come at a cost if lock Paul O'Connell finds himself cited for the vicious way he trampled on opposite number Archie Graham as the Ireland pack rumbled towards their opponents' line in the middle of the second half.

Namibian coach Dave Waterstone had promised a far more competitive effort from his team than they produced in their hammering by Argentina in their opening match.

But although the part-timers were not as outgunned quite so badly in the forwards, they had no answer to the speed of the Irish backs, who attempted to move the ball wide as often as conditions would allow.

Wing twins Denis Hickie and Shane Horgan both crossed, as did full-back Girvan Dempsey and his replacement John Kelly. There was even a first international try for prop Marcus Horan.

However, Brian O'Driscoll's barren run continues. The brilliant centre has not scored since touching down against the Italians in this year's Six Nations Championship.

O'Driscoll's value to the Irish side cannot just be measured in tries though and Argentina will have to find a way of stopping the brilliant Lions centre if they are to have any chance of registering a shock win.

Teams

Ireland: Dempsey, S. Horgan, O'Driscoll, Maggs, Hickie, O'Gara, Stringer, Horan, Wood, Hayes, O'Kelly, O'Connell, S. Easterby, Quinlan, Miller.

Replacements: Kelly for Dempsey (66), G. Easterby for Stringer (52), Byrne for Wood (52), Best for Hayes (73).

Not Used: O'Callaghan, Costello, Humphreys.

Tries: Quinlan 2, Dempsey, Hickie, Horan, Miller 2, G. Easterby, S. Horgan, Kelly.

Cons: O'Gara 7.

Namibia: Pedro, Mouton, Grobler, Powell, Dreyer, Wessels, Husselman, Lensing, Meyer, du Toit, Senekal, Graham, van der Merwe, Duvenhage, Furter.

Replacements: Afrika for Powell (73), Schrender for Wessels (62), Swanepoel for Husselman (62), Van Tonder for Meyer (26), Blaauw for du Toit (61), Lintvelt for Duvenhage (66).

Not Used: Van Lill.

Tries: Powell.

Cons: Wessels.

Sin Bin: Senekal (20).

Att: 48,000

Ref: Andrew Cole (Australia).