A thrilling finish was not greeted by the usual roars from the crowd though with no fans present -- one of the government's criteria for the return to some semblance of sporting normality.
Sullivan, like the 45 other jockeys involved in the 10-race card at Newcastle, had to have a temperature check on arrival and adhere to strict social-distancing rules.
He also wore a face mask during the race, another mandatory requirement as racing returned for the first time in 76 days.
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"I'm blowing a bit as obviously it's the first time I've ridden in a race for a while," Sullivan, who delivered the 22-1 winner, told Sky Sports Racing. "Hopefully that would have blown the cobwebs away.
"In this heat today, riding in the mask, it is very warm and after pulling up I pulled it down a little just to get a few breaths in. It wasn't too bad, though. It's manageable and it's the sort of thing that in a week you won't even notice it."
Champion jockey Oisin Murphy, also in action on Monday, said he was proud that horse racing was leading British sport back as the government loosens the coronavirus lockdown.
"It's time to return and I really feel we can come back in a safe way in a way the public can be proud of," he said.
"I've never ridden behind closed doors but when you're under pressure at a big meeting you tend to block the noise out anyway. It might be different for (Italian great) Frankie Dettori but I'll survive no problem." (Reporting by Martyn Herman; Editing by Ken Ferris)
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