January can prove a testing time for football teams and there managers, with games coming thick and fast.
With the transfer window open, and the African Cup of Nations "borrowing" some of their best players, team's title chances can wain quickly.
Manchester City's form has suffered slightly, and as a result they are now joined at the top of the table by rivals United.
Here are five things we learned about City this January that we may not have know before the turn of the year.
Aleksandar Kolarov in action v Everton
Up until the beginning of January, City had only lost once in the league (away to Chelsea) but as we creep slowly into February they have lost a further two Premier League games.
The 1-0 loss to Everton on deadline day, a result of a Darron Gibson goal, has meant that Gibson's former employers Man United are now level on points with their neighbours.
Kompany is shown a red card by referee Chris Foy
The suspension handed to captain Vincent Kompany, following his red card against rivals United in the FA Cup, led to City struggling defensively.
The centre back has been a key player for Mancini's side for over a year now and is widely considered to be the best central defender in the league.
It was a big task then for young Montenegrin Stefan Savic to fill his boots and having Kompany back will be a god-send for City fans.
However this does highlight a problem in the depth of Mancini's defensive options, and with the transfer window now shut, City can't afford any defensive layoffs.
When Mancini brandished an imaginary red-card in his side's away game at Wigan—which they won, unconvincingly, 1-0—many condemned his actions.
Widely accepted in European football, his card waving was frowned upon by the vast majority of pundits and punters, but Mancini refused to apologise.
After the match he said that his actions were no worse than Wayne Rooney's during the Kompany red card incident.
Kolo Toure blocks RVP's cross v Arsenal
This may seem an obvious one as the quality of the Toure brothers and their importance to City (Yaya in particular) has been known for some time, but their absence has been noticeable.
Both are involved in the African Cup of Nations with the Ivory Coast, who are now strong favourites to go on and win the tournament.
An early exit would mean the brothers would return before anticipated, but that looks unlikely.
Pizarro (right) v Sienna
With transfer deadline day producing little in the way of excitement or last minute deals compared to previous years, one thing can be said for sure—Mancini is finally pleased with his squad.
Since taking over at City in December 2009, the Italian has spent over £240m, but in this January transfer window he seemed far more controlled.
David Pizarro was the only name to come in, joining from Roma on loan until the end of the season.
The fans will be hoping the midfielder, who won the Serie A title under Mancini at Inter, can help guide them to their maiden championship.