Danish golfer Thorbjorn Olesen grabbed a woman's breast on a transatlantic flight after drinking alcohol and taking sleeping pills, a London court heard on Monday.
The Ryder Cup winner, 31, is also accused of pushing a member of the cabin crew and urinating on another passenger's seat on the plane from Nashville to London.
Olesen was on board with other professionals including Englishmen Ian Poulter, 45, and Justin Rose, 41, following a tournament in Memphis.
He denies sexual assault, assault by beating and being drunk on an aircraft on July 29, 2019.
Five-time European Tour winner Olesen, who lives in London, said he had no memory of his behaviour onboard the plane after drinking alcohol and taking sleeping pills, the jury was told.
His barrister, Trevor Burke QC, suggested his client's "bizarre behaviour" was due to the medication, whose side effects can include "sleep walking" and "amnesia".
A woman, who cannot be identified because she is an alleged victim of a sex offence, said in a statement Olesen grabbed her hand and started to kiss it before grabbing her on the breasts.
A member of the British Airways cabin crew, Sarah White, said: "During the flight Mr Olesen assaulted me and failed to listen to my instructions," she said.
"Through my 27 years of service, I have never come across such bad behaviour on board a flight."
Olesen was arrested after the plane landed and told police in an interview he could not remember what happened on board.
He said he had taken melatonin natural sleeping pills along with other sleeping pills and had five or six drinks, including red wine, beer and vodka with the intention to "knock himself out".
Olesen was initially suspended by the European Tour in August in 2019.
However, that ban was lifted in July 2020 due to the case being delayed by the coronavirus pandemic.
He has plummeted in the world rankings over the past two years from 62 at the time of the incident to 432.