Chelsea boss Carlo Ancelotti admitted his side were "lucky" as they came from behind to squeeze out a 2-1 win at Blackburn and keep their healthy Barclays Premier League lead intact.
Branislav Ivanovic headed the visitors' winner eight minutes from time just moments after Jason Roberts had spurned a clear chance to put the home side back in front.
Ancelotti said: "Blackburn could have scored before our goal and we were a little bit lucky. He [Roberts] could have closed the game."
But Ancelotti, who earlier this week insisted his in-form squad still had plenty of improvements to make, once again pointed out the need to move to another level.
"To win here was important because they were better. We were not great again. Blackburn put us under some pressure and we were not able to play our football.
"We knew it would be difficult to win here because Blackburn are a very good team with a lot of strength and physical ability and long balls.
"So it is very important to win here to maintain our position at the top. We are in good condition now and I hope we improve on this victory."
Ancelotti singled out Yury Zhirkov for special praise after the midfielder's sensational work down the left flank set up Ivanovic's chance to grab the points.
"We were (heading for) a draw then we had the fantastic play of Zhirkov and we were able to win this game," added Ancelotti. "He is playing good football and working for the team."