However, Clarke managed to sneak over right at the death to set up an enthralling encounter against two-time Heineken Cup champions Munster in Limerick next week.
Wilkinson, who has vowed to put an emphasis on enjoyment when he plays following such a lengthy lay-off, was back at the Falcons' Limerick training base on Wednesday.
Helped by the wind in the first half, Down hit the opening two points and while Limerick then levelled, Nicholson's goal gave the home side a three-point lead.