(THE GUARDIAN) - Simona Halep was hospitalised with dehydration following her Australian Open final defeat by Caroline Wozniacki on Saturday (Jan 27), forcing tournament officials to explain why the roof was left open at the Rod Laver Arena.

According to Tennis Australia, who released a statement on Sunday, the roof was left open because the wet bulb globe temperature - a mixture of temperature and humidity - did not pass the required threshold of 32.5 deg C to close it.

The Romanian, who needed the intervention of the doctor during her 7-6, 3-6, 6-4 defeat by Wozniacki, is understood to have spent four hours in hospital on Saturday evening.

After her loss to the Dane, Halep said: "Of course I'm sad I couldn't win today, but Caroline was better than me. For sure, I will fight and I have many years to go. Hopefully I will face another challenge like today."

Wozniacki will return to the top of the world rankings on Monday, six years after she first reached the summit.