Vincent Tabak, who denies murder but admits manslaughter, denied claims he had been aroused as he was asked to imagine his victim's last moments.
Miss Yeates's relatives watched in a hushed courtroom as he closed his eyes for 20 seconds - the time he claims it took to throttle her.
She may have been home for only a few minutes before Tabak was at her door with her cat, Bernard, the prosecution put to him.
On his second day in the witness box, Tabak, 33, said he was attracted to Miss Yeates, but claimed sex was not on his mind.
He told Bristol Crown Court Miss Yeates had been cheery and happy while flirting with him before the attack.
Prosecution QC Nigel Lickley then asked him: "What's the difficulty in accepting it is sexual?
"Is it because there are other sexual elements to what happened?"
Tabak replied: "There were no other sexual elements."
Mr Lickley asked: "Is the holding of her throat sexual in your mind? Did you derive sexual gratification from holding her throat?"
Tabak replied: "Definitely not."
Mr Lickley asked: "Were you sexually aroused when you were holding her throat with your hand over her mouth?"
The defendant replied: "Definitely not."
Mr Lickley asked: "Were you sexually aroused when you went to kiss her on the mouth?"
Tabak replied: "No ... I felt attracted to her, yes."
Mr Lickley went on to ask Tabak whether he thought she was attracted to him "because she made a comment about her cat getting into the wrong place".
Tabak said: "She was cheery, happy ... She made the comment (about the cat)."
Mr Lickley accused Tabak of telling lies, saying: "She showed no interest in you, Vincent Tabak."
Tabak said: "We were standing close to each other, she invited me in for a drink. She made a flirty comment. I thought she was flirtatious."
Tabak showed no emotion as he was shown a harrowing image of Miss Yeates's body in a foetal position at Flax Bourton mortuary, in Somerset.
He said he "cannot remember" how his arms were scarred, and denied claims there had been a struggle with Miss Yeates as he strangled her.
"There was no fight," he told the court. "There was no struggle."
Mr Lickley added: "How did you come by those marks on your arm?"
Tabak replied: "I can't remember that."
Tabak admitted he had misled police as a search was launched for her body and apologised for raising suspicions about landlord Christopher Jefferies.
"I am sorry I dragged him into this," he told the jury.
He said he was "in a state of panic, turmoil" after dumping her body on a snowy verge in Failand, Somerset, on December 17.
"I was exhausted that evening after moving Joanna's body," he said.
But - speaking in short sentences in a Dutch accent - he said he lied to police about having a nap after killing her.
"I did not have a sleep," he said. "I don't know why I did that."
Tabak admitted he knew what he was doing in trying to cover his tracks.
"I misled the police, yes," he said. "And it is dishonest."
Girlfriend Tanja Morson had no idea that her partner had become a killer, the court heard.
Tabak said Ms Morson did not get suspicious about him "sweating" and struggling to sleep.
Mr Lickley then asked the defendant who he was sorry for.
"For Joanna's parents, for Greg," Tabak said.
Mr Lickley replied: "What about yourself?"
Tabak said: "No."
Referring to Ms Morson, Tabak added: "I feel sorry for what I did to her yes, and for my parents."
Mr Lickley told Tabak he would have known as a child that holding Miss Yeates's throat would stop her breathing.
Tabak added: "It was not my intention to harm her. I just wanted to calm her down and stop her from screaming."
Mr Lickley suggested Tabak knew Miss Yeates's boyfriend was away for the weekend because Mr Jefferies had told him.
"Did you take the cat back to her flat, hence there was a conversation about the cat?" the QC asked.
Tabak replied: "No. The cat was not in my flat and that's not why I went to her door."
Tabak then manipulated and misled his girlfriend, Ms Morson, the prosecution claim.
"You just killed a woman intentionally. You said you were in mental distress and panicking, but not one sign of that to your girlfriend when you picked her up at 2am in the morning?" Mr Lickley asked.
"She detected nothing when you picked her up?"
Tabak said: "No, she probably didn't see anything."
Mr Lickley added: "And nothing the following day. When you went for lunch in Clifton and out in the evening to the party.
"Nothing detected by your girlfriend who had known you for how long?"
Tabak said: "For two years."
After Tabak left the stand, forensic pathologist Dr Nat Cary said there was no evidence to suggest she had been sexually assaulted.
Miss Yeates's body was found by dog walkers on Christmas Day last year. Tabak was arrested on January 20. The court was adjourned until Monday.
PA
