Newcastle goalkeeper Karl Darlow was forced into several good saves in the opening minutes but was outdone by his own man when Mason Mount fired a ball into the box and Fernandez bundled it in under pressure from Ben Chilwell on 10 minutes.
Chelsea continued to dominate but, despite chances for Abraham and Timo Werner, the sides went into the break with Newcastle's own goal as the only difference.
Werner had a chance to make it 2-0 on 53 minutes when he stole the ball from Fabian Schar. With just Darlow to beat he chose to cross the ball in to Hakim Ziyech which gave Ciaran Clark enough space to clear the ball.
The Germany international was crucial, however, to Chelsea doubling their lead on 65 minutes when he launched a quick counter attack down the left before cutting the ball inside to Abraham who slotted it home.
Werner's eventful day didn't end there as he had a goal disallowed for offside on 75 minutes.
"I'm pleased. It's a tough match to come here after the international break, the players have all been away," Chelsea coach Frank Lampard said after the game.
"We dominated the game, we could have scored more goals. But the lads dealt with it very well.
"We lost here last year so it's good progression to come here and get the right result."