"I never have said anything different", she said. She testified that "this was something I did not want known".
Swift, one of the most popular performers in the USA music business, spoke forcefully as she described the incident with Mueller.
When she finished meeting fans, Swift told her staff she had been groped, he said.
Mueller was sacked from his $150,000 per year job at KYGO-FM after the singer informed the management about what he did. She insisted that, contrary to Mueller's assertion that he may have just grazed her ribs with his elbow, his hand was indeed under her skirt. She continued: "What Mr Mueller did, like I said, was very intentional and the location was very intentional, and it happened very quickly".
She also rejected Mueller's contention that he may have touched her somewhere less inappropriate. Wiping away tears, she added: "She was really shaken". "I saw him. I didn't need to go look at the camera to see what he looked like".
"Swift's attorney, Douglas Baldridge, attacked the credibility of former Denver DJ David Mueller on Tuesday, asking jurors, "What's wrong with this picture?"
The trial, which began Monday, is the latest event in a drawn-out legal battle between Swift and Mueller. "Right there, that guy". "So in my opinion, I knew he touched her".
"I am critical of your client for sticking his hand under my skirt and grabbing my a*s", Swift said. Taylor is counter-suing, claiming assault and battery for "offensive and harmful physical contact".
Both claims are being weighed at the trial which is taking place in Denver, Colorado, and yesterday saw the third day of testimony.
Her testimony lasted about an hour. Mueller was the first to take the stand, describing his encounter with Swift as "weird and awkward".
"She (Taylor) couldn't believe that after he grabbed her, that she thanked them for being there", Andrea recalled. "And it went behind her, and her hand, or arm, went behind my arm". She alleges that, during a photo opp, he reached up her skirt and grabbed her butt.
Taylor also testified on Wednesday in a deposition in Denver and said, "It was not an accident, it was completely intentional, and I have never been so sure of anything in my life". "I had a good reputation in radio and I would like to get it back". Andrea Swift is a co-defendant in his lawsuit.
The incident changed the way Dent dealt with future meet-and-greets, he said. "We now have metal detectors. It scared us really badly".
Lyrics to some of Swift's most popular songs - such as "HATERZ GONNA HATE" and "I KNEW YOU WERE TROUBLE" - appeared later in the week.