Luiz Felipe Scolari may have a tough case to answer at the end of season over whether he has changed things for the better at Chelsea but the resurrection of Ashley Cole's best form will serve as one his first lines of defence.

Scolari's record is currently inferior to his predecessors Jose Mourinho and Avram Grant, yet he has succeeded where they failed by making Cole look like a world-class left-back in a blue shirt.

When Mourinho signed Cole from Arsenal three years ago in a deal which saw William Gallas and £5million go the other way, most Chelsea fans feared their north London rivals had got the better end of the bargain. His displays in the first two seasons did little to change that despite Gallas's problems at Emirates Stadium, while allegations of indiscretions off the pitch put further dents in the 28-year-old's popularity.

Cole's defending failed to impress on too many occasions and there was little sign of the attacking qualities seen under Arsenal boss Arsene Wenger.

But it has been a different story since Scolari replaced Grant in the summer.

Cole gives all the credit to Scolari and said: "The manager changed the way we play, he wants the full-backs to attack. People used to say that was my game and I'm really enjoying attacking again.

"This is the best I have played since I came to Chelsea. He has given me a lot more opportunity to get forward. We have shown that the more me and [Jose] Bosingwa get forward, it is hard for the opposition to mark us."

Of course, while Cole may be thriving, the defensive unit as a whole is not with nine goals conceded in their last six games.

It is over a month since they stopped the opposition from finding the net and the constant changing of the back four due to injuries hasn't helped.

There will be more upheaval against Middlesbrough tonight, with Ricardo Carvalho out with a hamstring strain, although John Terry returns to the side after a back problem. However, Cole feels there is no reason to panic. He said: "If we keep cleans sheets we will always have the firepower to score at the other end. We're not in a bad position and we think we'll turn our form around."

The departure of left-back rival Wayne Bridge to Manchester City this month has put even more onus on Cole to play every match until the end of the season.

Bridge's role at Stamford Bridge after Cole's arrival was to act mostly as cover and to provide the opportunity for his team-mate to get a rest on occasion.

But Cole prefers to play every week, adding: "I'd rather play every game, it's better for the brain and keeps me fit."