Many strikers are encouraged to shoot between the keeper's legs if he is braced to go either way on a shot. If they get it right it's an almost certain goal as there is no way the keeper can get down to the ball. I'm not saying that Andone did it deliberately but it was the best place to put the ball - so maybe luck didn't play such a big part?.
I think you're right in situations when you haven't got the whole goal to aim at. A keepers instinctive reaction will be to spread himself thinly across what part of the goal can be defended, and as such the ball can go straight through him when hit at his legs. However, last night to shoot right at the keeper with whole goal gaping simply gives the keeper a chance he shouldn't have.
Anyway, on to the next game where hopefully Andone plays a blinder after the confidence boost a goal can give.