Father Christmas, light on experience, has galloped during the running in the past, and Williamson was conscious of asking for too much.
"There were a few moments there when I thought I could have lost him but he seems like he wants to be there."
His father, Phil, watched the race by himself and he acknowledged the nerves could be a bit fraught when he watched one of his good horses racing.
"There's a little bit of ability there, so you try and make sure the Ts are crossed and the Is are dotted," he said.
Williamson was glad to see Father Christmas respond to the threat posed by Foreverman.
"That's the sort of horse that you'd hope he'd be; he's got that little bit of what you need to be a little bit better than average. Every race he's gone has been very good."
Every second race is penalty-free for a 3-year-old, so a fourth win is on the cards somewhere before the end of the month.
"That's the plan - we're being greedy, I know, but we'll have a lick at one more," the Totara trainer said.