The Belgian's striker's first was the result of a neat team move, Pedro's superb through ball splitting the Newcastle defence and leading to Eden Hazard slipping a pass inside to Alonso. Spaniard Alonso toed the ball first-time to Batshuayi, who made no mistake with a simple finish from eight yards out.
The Belgian forward scored his and Chelsea's second goal shortly before half-time when Pedro again initiated an attacking move, his pass releasing Hazard to run at a struggling defence. Batshuayi, up in support, looked set to run across his man but instead moved away, creating the space for Hazard to play him in before his shot took a huge deflection off Newcastle's Jamaal Lascelles and looped over goalkeeper Karl Darlow.
Any lingering doubt about the result was settled in the 72nd minute when Alonso whipped a left-footed free-kick over the defensive wall to make it 3-0. There have been suggestions that Batshuayi could be on his way out of Stamford Bridge during the closing days of the January transfer window.
But as for his immediate future, Batshuayi said he wanted to impress Blues manager Antonio Conte, telling BT Sport: "When I have a chance I take the chance and I work every day to be here. It's not for me to decide, it's the boss it's best that you ask Conte!"