Australia's Jana Pittman faded to fifth as Greece's Fani Halkia blazed to gold in the Olympic women's 400 metres hurdles before a roaring home crowd.

World champion Pittman led early before tiring badly in the final straight to clock 53.92 seconds as the new Greek heroine powered away to victory in 52.82.

Ionela Tirlea-Manolache of Romania was second in 53.38 and Tetiana Tereshchuk-Antipova of Ukraine was third in 53.44.

Pittman, 21, was racing in the final only 17 days after undergoing knee surgery after injuring herself at the Zurich grand prix meet on August 6.

She spent countless hours in rehabilitation at the Australian team camp in Italy before declaring herself fit and ready to race in Athens.

Pittman eased through the early rounds but the field was rocked when the fast-improving Halkia clocked 52.77 - the sixth fastest-time ever - in the semi-finals.

The Australian's personal best of 53.22 was set during her gold medal run at last year's world championships in Paris.

Pittman was philosophical about her run immediately afterwards.

"I was in a really good position but I didn't have it in the legs for the last 100," she told the Seven Network.

"It's a real heartbreak, but knowing where I've come from with the knee and everything ... it was just awesome to be in the final.

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