Eddie Howe made just one forced change to the side that beat Paris Saint-Germain 4-1 in the Champions League heading into the game with Elliot Anderson replacing the suspended Anthony Gordon on the left-wing.
West Ham took an early lead after Emerson caught out a charging Nick Pope before squaring the ball back to Tomas Soucek for a simple tap-in.
After an impressive run of form, The Magpies were lacking ideas in the opening 45 minutes at the London Stadium as they found themselves behind.
Here are the half-time player ratings from the match...
1. Nick Pope - 6
Caught out for West Ham’s opener by needlessly charging off his line. A silly way to end a run of three Premier League clean sheets in a row. Redeemed himself with some important saves towards the end as Newcastle looked to hang on.
2. Kieran Trippier - 7
Got into some decent areas to cross but wasn’t able to pick out a man from open play in the first half. His free-kick lead to Newcastle’s equaliser and put in a great cross on the volley to grab his sixth assist in four matches to set-up Isak.
3. Jamaal Lascelles - 6
Didn’t track Emerson’s run for West Ham’s opening goal. Did well in the air but struggled on the ground.
4. Fabian Schar - 8
Cut out the danger on a number of occasions. Could do nothing to stop the opening goal as he attempted to clear off the line.