After a frustrating first period in which neither side really hit top form, Dier popped up with a 66th-minute breakthrough after the home side failed to clear their lines from a corner.
Dier was playing in an advanced role alongside the highly effective Mousa Dembele by that stage after our starting central midfield pairing of Victor Wanyama and Harry Winks were forced off injured towards the end of the first half - the latter on a stretcher, after tumbling over and out of play between the two dugouts.
But we kept our focus and Son netted the second on 77 minutes after good work from Dele Alli to give us a bit of breathing space, while Dele himself went close to extending our lead on a couple of occasions as we bossed the game to see out a 2-0 victory.