Despite a blistering start in which Ramires saw a fine, long-range effort tipped wide by Ruddy, Norwich posed a serious threat in an open and entertaining game and could easily have snatched all three points themselves.
Bosingwa was a key attacking threat for the hosts from the off, twice rampaging down the right flank before he gave Chelsea the lead.
The home side worked the ball down the left and Lampard moved the ball across to Bosingwa, who drove his shot across goal and in off the far post.
Norwich responded with commendable composure and more than matched the Blues for the rest of the half.
Holt narrowly failed to connect with an inviting cross from Wes Hoolahan and Chris Martin forced a decent block from Hilario, who also kept out the follow-up strike from Kyle Naughton.
Norwich's Grant Holt hooks in the equaliser past a bemused Hilario
Holt had a headed effort saved but after the interval, the burly striker was able to celebrate a goal courtesy of a terrible gaffe by keeper Hilario.
The Portuguese raced from his goal straight into Branislav Ivanovic, who could only head the ball up in the air for Holt to hook it cleverly into the unguarded net.
Almost from the kick-off Chelsea piled forward down the left and from the centre Drogba was poleaxed by Ruddy.
After play finally resumed it was the Canaries who looked more likely to grab the winner.
Substitute Steve Morison should probably have earned them maximum points when he raced onto Holt's ball over the top but the Welsh international hesitated and John Terry dived in to clear.
Ruddy's replacement, Declan Rudd, was unable to stop Lampard's blasted strike and Chelsea then started to dominate.
Penalty was turning point - Lambert
Ivanovic somehow missed the target from six yards after a great dinked cross by Lampard before Mata finally broke Norwich's brave resistance, capitalising on Ritchie De Laet's error with the game well in to its 101st minute.
Chelsea manager Andre Villas-Boas:
"The 1-1 came against the running of the game.
"The impact of the 1-1 on the emotional part of the game is tremendous but, again, I'm very, very happy that the team is able to control their state of mind, to fight back, to show commitment and desire.
"We looked better overall in a 90-minute performance."
Norwich City manager Paul Lambert:
"I thought we were excellent, I really did.
"The penalty's turned the game. We could've been up 2-1, but I can't ask any more from the lads, the way they played. They came here and they thrived on it.
"We were up against a team that could potentially win the Premier League.
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