The 39-year-old suspect is accused of raping and murdering the victim during the summer of 2013 in the picturesque Upper Austrian town of Gmunden.
Allegedly, the pair met at a party in a tennis club in the town, soon after she finished mourning for the death of her husband.
The defendant is supposed to have referred to the clothing she was wearing, i.e. hotpants, and made several derogatory remarks towards her and her choice of attire.
According to the prosecution, the woman left the party, whereupon he followed her into the garden.
At this point, he is said to have demanded sex from her - on her refusal, he beat her unconscious with a blow to the head, and had sex with her anyway.
The victim never recovered from the blows and her subsequent fall, and died a few days later in hospital.
The defendant does not dispute having sex with the woman, but insists it was consensual. The DNA of the man was found under her fingernails, which is inconsistent with his testimony that he had sex with her from behind.
The man has been charged with wrongful death as a result of rape, and attempted murder. He faces up to 20 years in prison if convicted.
The town of Gmunden in Upper Austria. Photo: Wikimedia/Marion & Christoph Aistleitner