- Ronda Rousey loses fight to rival at event in Australia
- Rousey criticized for pre-bout antics
- American forced to spend night in hospital
- Holly Holm new world bantamweight champion
(CNN)It was a bad day at the office for Ronda Rousey.
If being on the wrong end of arguably the biggest upset in UFC history wasn't painful enough, Rousey was also forced to spend a night in hospital, while having to suffer abuse from Lady Gaga for her pre-bout antics.
Rousey, who had claimed to be "the best fighter in the whole world," lost her bantamweight title after being knocked out by Holly Holm in Melbourne, Australia, Sunday.
The fight-ending kick came 57 seconds into the second round, with Holm -- a former professional boxer turned mixed martial artist -- striking the 28-year-old American in the neck and sending her tumbling to the floor.
Rousey was forced to spend a night in hospital after suffering a busted lip from the knockout blow and reportedly saw a plastic surgeon Monday -- but she has vowed to come back stronger.
The shocking loss has ended Rousey's impressive run of 12 victories, some of which occurred within seconds of entering the ring -- in August, she knocked out Brazilian Bethe Correia in just 34 seconds, while taking only 14 seconds to dispatch rival Cat Zingano in February.
On top of having to cope with the biggest loss of her career, Rousey also had to deal with the barrage of criticism that came her way after snubbing Holm in the traditional pre-bout show of respect.
Pop star Lady Gaga led the way as viewers of the fight took great offense after Rousey refused to touch gloves with her opponent ahead of the clash.