With the kind of display Chelsea had against Manchester city before the international break, there's not supposed to be doubts if Chelsea can win Newcastle United. It is just because Chelsea has been on the lane of inconsistency for 2 seasons now, there's no need to trust them because of a week wonder.
This match is really hard to predict... Chelsea still hasn't completely won me over, even though their performance is gradually getting better. The return of some players from injury might be the key to the top-notch performance Chelsea could display.
If the performance shown against Manchester City can be maintained, then there is a big chance that Chelsea can beat Newcastle in the match played at St James Park. Moreover, several players have returned from injury so there is no reason for Mauricio Pochettino not to be able to beat Newcastle if Chelsea wants to move up to the top 4 of the Premier League standings.
Considering that Chelsea injured players are returning to play and also considering that Newcastle more players are being injured, Chelsea stands a good chance of winning the match between them and Newcastle United.