Chelsea last two matches very impressive, and perhaps this will make the Blues squad more confident against Newcastle. Apart from that, Chelsea also seems to have found their rhythm, because in 8 matches in all competitions the Chelsea team only one lost. This also proves that their performance already improve, so I'll probably favorite Chelsea in that match, and will bet on them.
Meanwhile, on the other side Eddie Howe may will be not too much pressure squad Newcastle to got winning against Chelsea, and in my opinion maybe they will be play safe because there is an important schedule in the UCL which requires Newcastle players to be fit.
Though Chelsea showed some changes in their pattern of play for their last two matches but that doesn't mean that they've picked form. Chelsea coach Mauricio Pochettino needs to put more of his attention on Chelsea's defense because that the major area they are lacking, if you check Chelsea's last 4 matches you will see that they concede losts of goal due to defensive errors. Mauricio Pochettino has coached Tottenham hotspurs and recorded good winnings with the club so I don't really know why he is having difficulties in transforming Chelsea like during his coaching career in Tottenham hotspurs, he made lots of success and understood the play nature of England teams so he shouldn't really be finding it hard to coordinate Chelsea.