Chelsea manager Jose Mourinho is taking nothing for granted even though his side rediscovered their mental toughness after a being given a scare by lowly Norwich.

When Leon McKenzie equalised for the Canaries 19 minutes into the second half to end Petr Cech's astonishing run of 1,025 minutes without conceding a league goal there was the sense another chink had appeared in the Chelsea armour.

The surprise failings against Newcastle in the FA Cup and Barcelona in the first leg of their last-16 Champions League showdown were on the brink of being magnified by a City side facing relegation.

Even last week's Carling Cup triumph was not without its problems and now here were an unfancied, unheralded Norwich seemingly on the brink of further agitating Mourinho.

Momentarily, despite knowing nearest title rivals Manchester United had dropped two points in a goalless draw at Crystal Palace, Chelsea appeared vulnerable.

But Chelsea responded with two goals in seven minutes. More than anything, that is what pleased Mourinho as he said: "They scored a good goal and it put some pressure on the result.

"But the team changed mentally at that moment and the good thing for me was our quick reaction.

"We reacted well, we showed intensity, desire and risk. We were too strong mentally for them, scoring two goals to kill the game."

That mentality would appear to be what is separating Chelsea from United and Arsenal, not least the eight-point gap that has opened up.

Yet while the finishing line may be in sight, Mourinho knows his side have not crossed it as he added: "If we think the job is done, then it's not done.

"We realise that we still have to win a few matches. We think game after game and we need another six victories and a draw to be sure."

The distance between Norwich and Chelsea was at times simply light years.

No wonder Canaries boss Nigel Worthington could not help but stand back and admire.

"Chelsea are a quality, quality team," extolled Worthington. "They are solid, patient and relentless and I can understand why they are top of the league. They will probably go on to win the league.

"Arsenal and Manchester United will make it hard for them, but the manager and the players have the focus, the belief is there.

"What he has done for Chelsea this year is turn individual talent into a team. That's the strength of the football club.

"He has been great for the English game and I've every respect for him because forget about the money he has spent, he has gelled world-class players into a team."

With the exception of one spell midway through the second half when McKenzie headed home the equaliser to cancel out Joe Cole's 20-yard strike in the 22nd minute, Chelsea looked champions-elect.

They answered City's brief riposte with two goals in seven minutes, firstly through Mateja Kezman two minutes after his arrival as a substitute, and then Ricardo Carvalho's first for the club.

McKenzie, despite laying claim to be the first player to beat Cech in the league since Thierry Henry in December, could find few crumbs of comfort.

"To stop his record he had going on was great," said McKenzie, who scored for the second successive match. "But they are the best because even at 1-1, when we were making a game of it, they went on to score goals.

"They've so much quality going forward and there's something within the team. They know they are the best.

"They will know they will get back into it. It's just a matter of when they step it up, and that's from the manager throughout the team. I don't see now why they won't win the league because Chelsea are different class."