Captain John Terry believes Chelsea have rediscovered their identity under Jose Mourinho to make a Barclays Premier League title tilt.
Chelsea beat Liverpool 2-1 on Sunday to move two points behind Arsenal at the halfway stage in a campaign which has seen Mourinho's men beat Manchester City and Liverpool and draw at Manchester United, Tottenham and Arsenal.
In the last two seasons Chelsea have struggled to remain in contention - in 2012 they finished 25 points behind winners City and in 2013 they were 14 points behind champions United, each time after being well adrift by Christmas - but Terry reckons the Blues now have the character to secure narrow wins, such as Sunday's.
"The last couple of years we've lost our identity a little bit," Terry told Chelsea TV.
"There's some good teams in the league and when you go 3-2 up (for example) it's important you get men behind the ball and dig in deep and not give them opportunities to really feed on. I think we're doing that really well at the moment.
"At times when we're looking really solid, getting the wide men in and then when we do break it's important for them to then go again and show their fresh legs going forward."
One of those wide men is Eden Hazard, who netted his eighth Premier League goal of the season to cancel out Martin Skrtel's opener, before Samuel Eto'o poked in the winner.
Terry was full of praise for Hazard, who has become "a complete player" since adopting the new-found defensive work ethic demanded by Mourinho.
"It's important you keep it tight at the back and you look for those type of players to create something or do something out of nothing," Terry added.
"He's been doing that all season (and) scoring. The last four or five games he's been really tracking back and really dug in.
"He's really dug in and added that to his game and made him the complete player."
Chelsea have tended to rise to the occasion this season against the bigger sides and did so again against Liverpool in a performance Terry believes was the Blues' best so far this term.
A ninth win from 10 home matches - West Brom the only blip, when Hazard converted a late penalty to earn a draw - extended Mourinho's unbeaten Premier League run at home to 70 games.
"I thought we were brilliant, for me the best we've played all season in the first half, especially after going a goal down," Terry said.
"I thought we responded really well. First half the pressure, the tempo, from everyone was excellent. And the fight and the desire to win.
"Away to Arsenal with five or 10 minutes to go you want a point; at home you always push and you want to win. That's why we've got such a good record (at home)."
Terry had a key role to play and did it well alongside Gary Cahill in central defence, starving Liverpool's prolific goalscorer Luis Suarez of chances.
It was Terry's 600th appearance for Chelsea after transcending eras of big spending prior to Roman Abramovich's 2003 takeover and since.
He added: "I'm really honoured to have played so many games for such a top team.
"When I came through here we were buying players and it was difficult to come through. I had to work hard to get where I am today.
"To still be fighting and playing and being involved is really special to me."
Asked if he will now target Ron Harris' club record of 795 appearances, the 33-year-old said: "No chance."
Chelsea's win was based on a collective endeavour and a defensive solidity helped by the deployment of David Luiz in midfield.
Mourinho had vowed not to select the Brazil defender in the position after his predecessor Rafael Benitez often did last term, but decided needs must against Liverpool.
Mourinho told Chelsea TV: "He can do it and he can do it very, very well. I saw last season and I like very, very much.
"The point for me is that the Chelsea we want to build is a Chelsea with a different profile.
"Without Ramires I needed intensity there. I needed his energy; (Frank) Lampard is not especially a fast player in terms of defensive transition.
"I needed David to do that. He had a fantastic game, not just on that, but also on playing football. He was magnificent."
Luiz is suspended for the trip to Southampton after picking up a fifth booking of the season against Liverpool, but Ramires is available again.
Frank Lampard (undisclosed) and Branislav Ivanovic (knee) are out after suffering injuries against Liverpool, the latter meaning Cesar Azpilicueta is likely to switch to right-back with Ashley Cole recalled at left-back.