24-year-old Andy Lawson passed away on Saturday after a crash in the second Supersport race of the Ulster Grand Prix event.
Lawson, the winner of the 2014 Junior Manx Grand Prix, finished the first Supersport race of the weekend in 16th on his Shirlaw's Kawasaki.
He then suffered a fatal crash on lap four of the second race, which was subsequently red-flagged.
"I am incredibly saddened by the news that Andy has succumbed to his injuries and my condolences are with his family, friends and race team," said clerk of the course Noel Johnston.
"He was a lovely guy and an up and coming rider, definitely one to watch.
“I had a quick chat with him just before that Supersport race began and he told me how much he was enjoying his first experience at Dundrod, and that he was taking it easy while he learned the course.
Lawson had also made his Isle of Man TT debut earlier in the year and was hospitalised with neck and arm injuries.
Kiwi Bruce Anstey was crowned Ulster Grand Prix winner in the main Superbike class.