Sutcliffe alleged that Sheeran "borrows ideas and throws them into his songs. Sometimes he will acknowledge it but sometimes he won't".
But today, Sheeran's lawyer Ian Mill asked him if he accepted that he had done this.
Sheeran said "if Mr Sutcliffe would have done his research", he would have known there were "lots" of unknown artists that he had run parts of his songs by.
"All those examples are not famous artists that we've cleared songs with. That's what I have to say on that," he said.
Sheeran also denied that he altered others' words and music to appear original and went on to deny that he was aware of Chokri, who performs under the name Sami Switch.
Sutcliffe pointed out that they had appeared on the YouTube channel SBTV at around the same time, Chokri had messaged him on Twitter, they had the same friends, and Sheeran had allegedly shouted his name during a performance.
"This is all stuff you're saying, this isn't stuff that's true," Sheeran said.
Sutcliffe asked him: "You're saying you definitely weren't aware of him, rather than you've forgotten that you're aware of him?"
"Yes," Mr Sheeran said.
Sheeran denied that the late founder of SBTV YouTube channel Jamal Edwards had shared Chokri's song Oh Why with him.
Edwards died last month and was described in court as Sheeran's "best friend".
Sutcliffe continued, "It's just not credible, Mr Sheeran. This is your best friend who was very much at the centre of the UK scene. You're saying he didn't start to share music with you until last year?"
"Yes, that's what I'm saying," Sheeran replied, adding that they would "talk about football, talk about his mum, talk about theatre".
"I suggest it's entirely possible that Jamal Edwards shared Oh Why with you, isn't it?" Sutcliffe said.
"No," Mr Sheeran replied.
Sheeran denied Chokri's claim that they had met at a party in central London.
In his written witness statement, he said he "always tried to be completely fair in crediting anyone who makes any contribution to any song I write ... I have even given credits to people who I believe may have been no more than a mere influence for a songwriting element".
Sheeran described his songs as "excitement bottles" with "no premeditated thought process" and that almost all of them were written in under two hours.
He and his co-writers launched legal proceedings in 2018, asking the High Court to confirm they had not infringed any copyright.
A few months later, Chokri and O'Donoghue issued their own claim for "copyright infringement, damages and an account of profits in relation to the alleged infringement".
The trial continues.
