Andre Villas-Boas believes his Chelsea side are back in the thick of the title race following their 2-1 win over Premier League leaders Manchester City.
Victory over saw Chelsea move to within seven points of City who suffered their first defeat in 15 league games so far this season at Stamford Bridge here on Monday.
And having also secured their passage to the knockout stages of the Champions League as winners of their qualifying group, Chelsea manager Villas-Boas is convinced the London club's fortunes have been transformed after a difficult few weeks when his long-term future was questioned.
"It's been a good win for us. It changes our challenge for the Premier League," said Villas-Boas of a victory achieved through goals from Raul Meireles and a Frank Lampard penalty against a City side reduced to 10 men following the 58th minute dismissal of Gael Clichy.
"Seven points in this Premier League when there are so many teams competing for the title is nothing," Portuguese boss Villas-Boas said.
"Man City play Arsenal in the next week, we play Tottenham soon.
"The reality is we have to agree there have never been so many teams competing for the title.
"Man City are competing, Tottenham are competing, Liverpool look solid, Arsenal are coming from the death to recover again their title hopes.
"I could be wrong but I don't recall so many teams feeling so strong."
However, he warned: "For our title challenge to still be alive we will have to continue to be competent during our December fixtures and then we can look at it in January to see where we are and see if things are back on track again.
"But I was say reducing it seven points is good for us but we have to continue to perform."
Mario Balotelli had fired City ahead after fewer than two minute but Meireles equalised in the 34th minute before Lampard completed the comeback from the spot in the 83rd minute.
City manager Roberto Mancini insisted his side's challenge would not be knocked off course by one defeat.
He added this game turned on referee Mark Clattenburg's failure to award a first half penalty when David Silva appeared to be tripped by Jose Bosingwa.
"It's unusual that a team comes here and plays against Chelsea, who are a top team, and dominate the game.
"When one team plays very well and has the chance to score it is a big penalty. After, we can lose or win because when you play against Chelsea they are a good team. But not like this."
Mancini confirmed Balotelli would not be punished for breaching a club curfew two days before the game.
And the manager denied his side have a discipline problem after Clichy became the third City player to be dismissed in six league games.
"It's clear we should pay attention because the referees at the moment are very concentrated on this situation."
Villas-Boas meanwhile paid tribute to striker Nicolas Anelka, who will leave the club in January after agreeing a move to Chinese side Shanghai Shenhua.
"He's reached an agreement with Shanghai to join them in January. We have decided to part company but we are honoured to have had Nico here."
And denying Anelka and Alex, who has also submitted a transfer request, had been frozen out on the training ground, Villas-Boas added: "We just decided based on what we had on training to concentrate on the players who would be with us in January. There is no bad treatment of Nico and Alex."