Angelique Kerber said being forced into hard hotel quarantine contributed to her demise at the Australian Open Monday after the former champion crashed out to Bernarda Pera.

The 2016 Australian Open winner, seeded 23 at Melbourne Park, was in disarray as she succumbed 6-0, 6-4 in just one hour and 10 minutes against American Pera, ranked 63.

The German, who had 25 unforced errors and seven double faults, lost the first nine games as she faced the humiliating prospect of a 6-0, 6-0 ‘double bagel’ before her attempts at a comeback were thwarted by the 26-year-old, who did not undergo a hard quarantine.

Kerber was one of 72 players unable to leave their rooms during quarantine after being on a flight to Melbourne where a passenger tested positive for COVID-19. Other players were allowed outside for daily five-hour training blocks.

“Definitely, yes,” the 33-year-old said when asked if the lockdown had an impact on her performance.

“You feel it, especially if you play a real match where it counts and you play the first match in a Grand Slam against an opponent who doesn’t stay in the hard lockdown,” she said.

“I was not feeling the rhythm that I was before the two weeks, to be honest.”

The three-time Grand Slam winner said she would have reconsidered travelling to Australia if she had known what lay ahead.

“Looking back, I had not planned the two weeks hard quarantine,” she said.

“If I knew that before… to stay two weeks in the hard quarantine without hitting a ball, maybe I would think twice about that.”

It was the second consecutive first-round Grand Slam defeat for Kerber, who lost to Kaja Juvan at the French Open.

Pera plays Zarina Diyas of Kazakhstan in the second round.