Police said the man flagged down the passing driver on Rawson Road in Guildford at about 4.30pm.
Emergency services were called and the man was treated for injuries “consistent with an assault” before he was taken to Westmead Hospital in a stable condition.
Police arrested a 61-year-old man outside a residential housing complex shortly after.
Officers established a crime scene at a unit inside the complex which is the home of the older man.
Police will allege the men were known to each other, and had entered the unit at about 7pm on Saturday.
“Whilst at the unit an argument allegedly developed between the two,” police said.
The younger man was allegedly assaulted with a number of items including a pair of scissors and a golf club.
Police allege the 46-year-old man was prevented from leaving the unit before being able to flee.
The older man has been charged with aggravated sexual assault inflicting actual bodily harm on the victim, and taking a person with intent to commit a serious indictable offence.
He has been refused bail to appear at Parramatta Local Court today.