A seriously injured giant panda which was in a coma for 54 hours at a zoo in southwest China's Sichuan Province has regained consciousness.

Two-year-old Pai Pai, bred in captivity at Chengdu Research Base of Giant Panda Breeding, was comatosed after he fell off a tree more than 4 meters tall last Thursday evening.

Vets at the base said his heart rate fell to 30 beats a minute, far below the normal rate of 80-220 beats.

Despite intravenous injections of vitamins and nutrients, Pai Pai's situation worsened around midnight and vets feared he could die at any moment.

The research base then invited trauma and neurological experts from two leading hospitals in Chengdu to help.

By Saturday morning, Pai Pai's heart rate and temperature were back to normal, but he still remained unconscious.

In a desperate attempt to bring the bear back to life, panda carers kept massaging him throughout the day. By midnight Saturday, they felt a weak movement in one of his legs.

Pai Pai opened his eyes at 1:30 a.m. Sunday, to the applause and screams of doctors and vets who had spent 54 hours with him. He moved his limbs and struggled to stand up.

"We couldn't be happier," said panda expert Huang Xiangming, "not even when a cub is born."

Huang said Pai Pai set two records: the longest coma a panda ever endured and a record volume of 10,500 milliliters of intravenous shots.

Pai Pai began tucking into bamboo leaves Tuesday and appeared much healthier. Huang said he was out of danger, but still needed a couple of weeks to fully recover.