For Andre Agassi, victory in his fourth round match at the Australian Open was a bit like taking a particularly unpleasant medicine.

It tasted bad, but he knew it was good for him.

Agassi earned his place in the quarter-finals at the expense to Argentina's Guillermo Coria who retired during the second set when down 6-1 3-1.

Always the sporting gentleman, Agassi said he would have preferred a more honourable advance to the last eight of a men's singles championship which decimated by injury before it began and getting worse every day.

Coria's untimely exit with a badly blistered foot was the ninth such departure in the first seven days of the Open.

The spate of injuries followed the pre-tournament withdrawals of Pete Sampras, Tommy Haas, Tim Henman and defending champion Thomas Johansson.

While he welcomed the opportunity to move a step closer to his eighth grand slam title, Agassi, ever the purist, would have preferred to have done it properly.

"It's not ideal to not finish for a number of reasons," Agassi said.

Prominent in Agassi's mind was his own preparation, but his well-developed sense of decency also told him a drastically shortened match was also bad for the tournament and the spectators.

"The fact that you're out here playing such a great tournament ... centre court, all the people ... you want to push yourself," he said.

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