Antonio Conte's side not at their best as they face replay with their Championship opponents who are disappointed not to have won.
Chelsea endure frustrating night in goalless FA Cup tie with Norwich
Premier League champions Chelsea were held to a goalless draw away to second-tier Norwich City in a dull FA Cup third round tie on Saturday.
Manager Antonio Conte had made nine changes from the 2-2 draw with Arsenal in the league on Wednesday, keeping only Gary Cahill and Tiemoue Bakayoko in the team.
Norwich, relegated to the Championship (second tier) two years ago after one season back in the Premier League, had slightly the better of a quiet first half.
Goalkeeper Angus Gunn saved well from Willian in one of the few clear-cut chances either side made, and bringing on Alvaro Morata from a youthful substitutes' bench did not have the desired effect for Conte's side.
They now face a replay in London to add to a busy January, which also includes a two-leg League Cup semi-final against Arsenal.
Norwich City manager Daniel Farke told BBC Sport: "To be honest I'm a bit disappointed it was not a win for us. We had an outstanding game and in the first half we dominated, and didn't give a chance away.
"It was pretty close to a celebrating day, so I praise my lads but we are a bit sad that we didn't win. It was important to be good in possession, especially against a good possession team like Chelsea.
"A replay is a good thing for the club, maybe it doesn't help us for the league but I'm a big believer in the cup. Today it was a bigger chance to beat Chelsea than in the away game, but we will try everything."