If you needed evidence of just how things can change over the course of a season then look no further than Chelsea and Aston Villa.
When the two clubs met in mid-October the goalless stalemate at Villa Park sent Chelsea five points clear at the top of the table while Villa remained eighth.
Now, following Sunday's 3-3 draw in the reverse fixture, the champions are fifth in the table, six points behind leaders Manchester United, while Gerard Houllier's side are still firmly in the bottom half.
To understand Chelsea's plight you need only look at the contrasting emotions in the final few minutes at Stamford Bridge yesterday.
The team celebrated John Terry's 89th-minute goal to put them 3-2 up by dashing over to celebrate with manager Carlo Ancelotti as though they had just won a trophy.
Moments later, as Ciaran Clark was allowed to saunter through a static line of blue training cones and head home his injury-time equaliser, heads dropped and Terry and Didier Drogba left the field at each other's throats.
Cheap goals conceded, late wins lost, players in-fighting - this is not the ruthless Chelsea machine of old, or even of earlier this season. The efficient unit which once inspired little love but plenty of respect feels like a distant memory, so much so that Ancelotti is already looking to a fixture which is two months away as the point when they can get their title chase back on track.
Chelsea are due to play United on March 1, by which time the Red Devils could be out of sight - but Ancelotti is targeting that match as one they must win.
He said: "First United have to win (their game in hand). Second I think the gap is not small but everything is open.
"Obviously we have to beat United here (in March) then we can say something about the title. It is not over because we are improving and we can save something this season."
It is hard to share in that optimism. Chelsea have only won one of their four matches against the other sides in the top five of the table this season, and they are still to play United twice. Even bringing up a match rearranged for spring at the start of the year shows just how far the destination of the title is out of their hands. Unlike United two seasons ago, Chelsea have already dropped far too many points to flat-track bully their way to retaining their crown.
The Italian coach admitted that his squad is in desperate need of replenishment now that the January transfer window is open, but even doing so in the big-spending manner which turned Chelsea into such a force over the past decade could now prove a tall order.
Not only are owner Roman Abramovich's purse strings so much tighter, but Manchester City have the power to outbid them for anyone they choose. Even with the big-money addition of Edin Dzeko set to be sealed as early as this week, City can comfortably match Chelsea in signing any of their targets, such as Benfica defender David Luiz. Besides, the £20 million shelled out for the infuriatingly inconsistent Ramires last summer will hardly encourage Abramovich to wield the chequebook too liberally again this month.
Injury to Alex and the suspension of Branislav Ivanovic forced him to field 19-year-old centre-back Jeffrey Bruma against Villa, with the ensuing result further proof that Chelsea's youth policy, led by the outgoing Frank Arnesen, is a long way off providing what Abramovich must have hoped for by this stage.
Still, as the sharp dip in Chelsea's own fortunes has shown, there is still plenty of time between now and the end of the season for the pendulum to swing back in their favour.
They are only one point behind fourth-placed Tottenham, who seemingly everyone (including, they hope, David Beckham) except Early Doors believes are in with a shout of claiming the title.
Their faltering defence has plenty of room for improvement, whereas Arsenal's is playing about as well as it can.
They have a squad full of players who have experienced several title-winning seasons in years gone by as well as claiming the double last term, a factor so often cited as the reason why United remain unbeaten despite so often playing below par and why this season is too soon for City.
They may be no one's favourites any more, and rightly so, but it would be foolhardy to completely write Chelsea off at this stage.
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QUOTE OF THE DAY: "Blackburn have contacted us. There is also other interest in England but this is confidential." - Ronaldinho's brother and agent Roberto de Assis reveals the amazing news that Rovers owners Venky's have made an approach for the Milan and Brazil has-been, offering him £130,000 a week. And here we were thinking they knew nothing about football.
FOREIGN VIEW: "If his tendons hold out, I think he could get to 700." - Barcelona coach Pep Guardiola on his star playmaker Xavi Hernandez, whose 549th appearance for the club in the 2-1 win against Levante equalled the club record held by Migueli. The Blaugrana playmaker's 156 completed passes last night were not only more than the entire Levante team, but also the most by a player in a single Liga match since Opta started compiling such statistics in 2006.
COMING UP: Catch up on all the action you might have missed this weekend with our highlights of each and every Premier League game, plus a rundown of the top five goals, saves and the Team of the Week.
Paul Parker will be giving his views on the weekend's action, and The Fantasist will be giving the lowdown on all the latest injury and suspension news ahead of the midweek round of fixtures.
Later on we'll be bringing you live coverage of each of the day's Championship fixtures (15:00), as well as full commentary on Villarreal v Almeria (19:00) and Getafe v Real Madrid (21:00) in La Liga.