Chelsea captain Gary Cahill speaking to BT Sport: "It was decent in the end. I thought we started a bit rusty. We needed that win and to progress is the most important.
"We need to try to reach the final rounds in this having gone out of the EFL Cup the other night so this is very important.
"After the first 10-15 minutes we got on with it. Especially Michy, he took his opportunity today."
The key stats
◾Chelsea have now reached the FA Cup fifth round in 18 of their last 20 seasons, only failing to do so in 2011 and 2015.
◾Michy Batshuayi has scored more FA Cup goals for Chelsea with five than any other player under Antonio Conte's tutelage.
◾Newcastle have now lost six consecutive games at Stamford Bridge in all competitions, conceding 18 goals while scoring just twice.
◾Marcos Alonso has been directly involved in 10 goals this season in all competitions, more than any other defender in the Premier League.
◾Alonso has scored three goals from direct free-kicks in all competitions this season, more than any other Premier League player. Philippe Coutinho with two is the only other player to have scored more than one.
◾Eden Hazard has been directly involved in nine goals in his last nine games against Newcastle United in all competitions.
Chelsea stay at Stamford Bridge for Wednesday's return to the Premier League against Bournemouth (19:45 GMT), while Newcastle entertain Burnley at the same time.