The thing that worries me is that they were losing games with Sherwood due to silly, individual mistakes which Sherwood kept repeating (like the one which lead to our goal, which was similar to the Chelsea, Palace and Swansea goals they conceded). When you add up those mistakes alone, it costed them around 4 points...which would put them near safety.
I think Garde may not be perfect but unlike Sherwood he is no fool. He is a proper footballing manager unlike the wise-talker Sherwood and looks to have more layers to him in terms of tactics and philosophy, rather than the classic "go and work hard lads" line which Sherwood used to pedal.
This is why I think they can stay up, as sadly things can only get better for them.