The Blues survived an early scare when Asmir Begovic smothered Angol’s poor effort from Marcus Maddison’s right-wing cross.

However, Chelsea were soon causing problems at corners as Gary Cahill and Terry – making his 50th FA Cup start – forced saves from McGee.

McGee could do nothing about Chelsea’s first goal, though. Chalobah’s long-range strike was parried into the path of Pedro, who rifled the follow-up into the top-right corner after cleverly selling the defender a dummy.

Batshuayi and Ruben Loftus-Cheek were both denied by McGee, before Pedro somehow struck the crossbar from six yards.

But Chelsea were 2-0 up shortly before half-time. Loftus-Cheek laid Branislav Ivanovic’s cross into Batshuayi’s path and the Belgium striker angled his shot powerfully past McGee.

Batshuayi laid on a great chance for Loftus-Cheek two minutes after the restart, but the midfielder slotted his shot just wide.

That miss was soon forgotten as Willian extended the lead after 51 minutes. Peterborough’s high line was exposed as Pedro raced clear down the left and he found Willian, who was given too much space to bend a fine finish across McGee.

Terry’s clumsy foul on Angol saw the skipper earn a straight red card and Peterborough’s hopes of an unlikely fightback were boosted when Nichols slotted home Michael Smith’s cross to make it 3-1.

Pedro extinguished the visitors’ chances with 15 minutes to go, however, stroking home from the edge of the area from Batshuayi’s lay-off as Chelsea, who have lost just one of their last 35 FA Cup home games against lower-league opposition, cruised into the fourth round.