Nor was he done there, as he charged through Leinster ranks in the latter stages to collect his fourth and wrap up a bonus-point 33-25 Guinness PRO12 win.
Seymour's early-season form is unrivalled across the northern hemisphere, as he added to his double on the opening day against Connacht.
But the Glasgow flyer admits more than a slice of fortune was involved in his heroics.
"Matt Taylor [Glasgow defence coach] will make no secret of the fact that his view on intercepts is if you get it it's the best thing you could have done, but if you miss it it's the worst thing you could have done," said Seymour.
"It was just a little bit of alignment. You can take all day, but there's a lot of luck in intercepts. I managed to get the read on it and it fell into my hands, but it's not something you're going to gamble on that often."
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