Anyone seeking to understand Chelsea's steady return to form under interim manager Guus Hiddink will find a partial explanation in the unassuming figure of holding midfielder John Mikel Obi.
Having started just two of Chelsea's final 16 Premier League games under Jose Mourinho, Mikel has started nine of 12 under Hiddink in the only notable non-enforced personnel change that the Dutchman has made to the starting XI.
As well as being unbeaten in their 12 league games to date under Hiddink, Chelsea's average number of goals conceded per game has dropped from 1.625 to 1, and Mikel's defensive nous has been an important factor.
"He's the ideal player to bring balance to the team," Hiddink said earlier this year.
"He knows where the strength of the opponent is and he knows exactly how to cope with that.
"He doesn't do it in a very brutal way — he's very, very elegant. What I like to see very much is not just a quality player, but a player who can defend so smoothly. It's beautiful to see."
Whereas Mourinho habitually paired Nemanja Matic and Cesc Fabregas, Hiddink has used Mikel, 28, alongside Matic — another leggy enforcer — and moved Fabregas upfield.
It is a configuration that has helped Chelsea climb to 10th in the league, kindling hope that they may yet succeed in overturning a 2-1 deficit in Wednesday's Champions League clash at home to Paris Saint-Germain.
Mikel missed the two previous Champions League ties with PSG over the last two seasons. An unused substitute in both legs of the quarter-final in 2013-14, he was recovering from knee surgery last season.
But he has already made his mark on this season's last 16 tie, having been the source of two goals in the first leg at Parc des Princes.
I NEVER GET UPSET
The Nigeria international conceded the free-kick from which Zlatan Ibrahimovic put PSG ahead, the Swede's shot deflecting in off his foot, before slamming home from close range to earn Chelsea a precious away goal.
Mikel has scored only six goals in a Chelsea career spanning almost 10 years, but he becomes a more expansive player when he pulls on the green number 10 shirt of his country, with whom he won the 2013 Africa Cup of Nations.
It was for his playmaking qualities that an 18-year-old Mikel was awarded the Silver Ball at the 2005 World Youth Championship in the Netherlands, losing out on the top individual award to a young Argentine forward called Lionel Messi.
Those abilities prompted an extraordinary transfer tug-of-war between Chelsea, Manchester United and Norwegian club Lyn Oslo, his then employers, in 2005.
Chelsea eventually agreed to pay £12 million ($17.1 million, 15.5 million euros) to United and £4 million to Lyn for his contract, but not before he had appeared at a press conference wearing a red United shirt with 'MIKEL 21' stamped on the back.
Eleven years on, he has become part of the Chelsea furniture and is one of only two survivors — along with captain John Terry — from Mourinho's first stint at the club between 2004 and 2007.
While it was Mourinho who made him a Chelsea player, Mikel has made no secret of his relief over Hiddink's arrival as a replacement for the caustic Portuguese.
"Guus has come in again and settled things down," he said recently.
"Players feel free to play and free to take responsibility and thrive on that, but he's done it in a very relaxed way, which is sometimes what players need. It feels great to be back in the side."