Ferris' second-half appearance, his first since November 2012 due to an ankle injury, played a vital role in the fourth and final try as Tom Court burrowed over.
Earlier Anscombe's troops had cut their Welsh rivals to shreds in the first half as Paddy Jackson, released by Ireland, crossed twice and also laid on the third score for Tommy Bowe.
Gareth Davies' opportunist score kept the Welsh region interested but there was no doubting the star of night as Ferris' cameo after the interval received the biggest roar of the night.
"He is huge and a big part of Ulster. To see him after all the hard work he's been through," said Anscombe.
"The crowd love him. Hopefully the ankle pulls up well tomorrow."
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Guinness PRO12 Ulster News
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