Dad wasn't real happy when son took off from his economical position back in the field to test Winterfell for the lead, a tactic that was never going to work and probably gave Majestic Man more of a headache than Phil would have liked, especially as he battled so bravely into third as Winterfell strode to a national record.
"I wasn't thrilled at the time but the good news is the horse has come through it great," says Williamson senior, one of the more jovial of harness trainers.
When the men from Oamaru meet up at Alexandra Park for tomorrow night's $150,000 Inter Dominion Trotting Final not many words will need to be exchanged. They will both be on the same page, the plan apparent.
Phil expects Brad to get Majestic Man off the gate fast from barrier four, lead as easily as possible then probably hand that role to Winterfell if the favourite is trotting well and gets serious. If it works out that way, and it often doesn't, then Majestic Man should get his chance up the passing lane to chase down the $1.90 favourite.
"That looks like what might happen," says Williamson.
It is also what the market has priced to happen, with the pair dominating betting.
If that scenario unfolds then Phil is hoping some of the big guns who fared worse in the draws rachet up the mid-race pressure, leaving Winterfell vulnerable for Brad's late launch. "There are plenty of other good horses in the race and you can't imagine horses like Massive Metro and Paramount King are just going to sit back. So if it works out Winterfell is in front and we trail I hope they all come around, even just having horses up outside you can make a leader spark up.
"That is another reason we want to be lead or trail, because if we don't get to the markers we risk being pushed back when the moves come."
The making of the race could be Marcoola, who has been driven cold in this series but whose most dramatic wins have come when he has got rolling a long way from home, whether that be in front or from back in the field.
All things being equal if Winterfell, who still isn't foolproof, leads and trots as well as last Friday night he might simply be too good.
But odd things can happen in Inter Dominion Trotting Finals and if that happens the Williamsons may not be talking after the race. They might be laughing.