The Magpies started the game reasonably enough and came close to opening the scoring through Jonjo Shelvey, but Batshuayi’s poacher’s finish set Antonio Conte’s side on their way.
The Belgian forward notched another with the help of a Jamaal Lascelles deflection, and Alonso’s superb set-piece midway through the second half made sure of the Blues’ place in the last 16.
Newcastle have still not been as far as that since the 2005/06 campaign. In the same time, the Blues have made it to five finals, winning four.
The opening quarter of the game passed by largely without incident, something summed up by Eden Hazard’s free kick from a promising position on the edge of the penalty area, which failed to get as far as Karl Darlow as the Magpies’ wall held firm.
Newcastle looked fairly solid early on, and almost took the lead 25 minutes in. Massadio Haïdara – making his first start in exactly a year – advanced to the left byline before picking out Shelvey, whose near-post strike was palmed just wide by Willy Caballero.
But, out of nothing, Chelsea took the lead just after the half-hour mark. Pedro split the Magpies’ backline with a superb ball from deep, which Hazard gathered on the left of the penalty area. The Belgian teed up Alonso, who unselfishly squared for Batshuayi to tap in from eight yards out.
Dwight Gayle brought a low stop out of Caballero as Newcastle looked to respond, before Antonio Rüdiger curled narrowly wide for the home side after cutting in from the right, Darlow seemingly beaten.
The Blues were, in truth, a little fortunate to lead 2-0 at the break, though. After a United attack broke down, Pedro set Hazard away on the counter. He played in Batshuayi, whose low-struck effort likely wouldn’t have troubled Darlow. However, Lascelles’ attempted intervention only succeeded in diverting the ball over the head of the United stopper, and into the back of the net.
There was still time for Shelvey and Chancel Mbemba to come close for Newcastle as a slow-burning first half came to life late on.
The second period started in similar fashion. Pedro almost added a third for Chelsea within five minutes of the restart, firing narrowly over the top after Rüdiger’s cross was only half-cleared. Then, at the other end, Shelvey nodded off-target from an Issac Hayden delivery, before Alonso saw a sweetly-struck volley parried by Darlow.
There was little Darlow could do to keep out the Spaniard’s next effort, though. With just less than 20 minutes remaining, Davide Zappacosta cut in from the right and was felled by Henri Saivet. Alonso let fly from 25 yards, and superbly guided the ball into the top corner of the net.
With ten minutes to play, Darlow was called into action twice in succession, rushing off his line to deny Pedro, before producing an acrobatic stop to tip Zappacosta’s effort over the crossbar.
The Magpies’ attacking spark dissipated as the clock ticked by, something they will need to rediscover quickly, with Burnley set to visit St. James’ Park in the Premier League on Wednesday.
