It's now that things get interesting for managers across Europe.
How to keep your squad fresh even though you're fighting in three or four competitions, how to ride through the inevitable injuries and suspensions and keep up the motivation through the cold winter months, how to retain the players you want to keep and let the others go as the transfer window opens in World Cup year.
It's a fascinating picture in La Liga. At this stage last season, Barcelona led Atletico Madrid by nine points and Real Madrid by 16. Not so easy this time around - just goal difference keeps Tata Martino's side above Atletico coming out of the Christmas break, and Real sit five points adrift, having only lost to those two in the league and dropped just four points otherwise.
Barca had their mini-wobble at the end of December, but have responded with five straight wins in all competitions, scoring 20.
And remember that Lionel Messi is still recovering from injury over in Argentina, Victor Valdes has also been out, and Neymar also served a one-match ban during that time. When all three are available, we'll see if they can rediscover that extra gear.
Diego Simeone's miracle work at the Estadio Vicente Calderon continues, with just one defeat all season in mid-October, Diego Costa leading the Pichichi (league scorer) standings with 19 goals and others chipping in too.
Keeping the core of the Atletico squad together is key for Simeone, resisting overtures from 'bigger' clubs not just for Costa, but also supporting cast members like Koke, Raul Garcia and on-loan Chelsea goalkeeper Thibaut Courtois.
Real Madrid may well dip into the transfer market again in a bid to bolster their squad and their title hopes. But departures from the Bernabeu may be more likely, particularly the likes of Fabio Coentrao and Iker Casillas, perhaps also Angel di Maria and Alvaro Morata.
Boss Carlo Ancelotti has other issues to deal with on the pitch - his team's habit of conceding against lesser league opposition and Sergio Ramos' disciplinary record.
At the sharp end, there are causes for concern for Real Betis and Rayo Vallecano, seventh and eighth last season, and now bottom and second-bottom.
Betis have already replaced Pepe Mel with Juan Carlos Garrido, and Rayo could do likewise - Paco Jemez needs results, but looking on the bright side, the La Liga table is still relatively tight, with just 10 points covering the bottom 11 teams, and a decent run in the Copa del Rey could be very timely indeed.
It's all to play for in Ligue 1, with Paris Saint-Germain only three points clear, thanks to Monaco's surprising defeat at home to Valenciennes last time out and PSG's draw with third-placed Lille.
For Laurent Blanc's side, the Edinson Cavani-Zlatan Ibrahimovic axis is one of the most feared in Europe and continues to fire freely, Zlatan perhaps trying to prove what the planet will be missing at the World Cup, which apparently isn't worth watching without him in it.
Again, ordering of priorities could go some way to deciding their season: Bayer Leverkusen is a relatively winnable round-of-16 tie in the UEFA Champions League, and you'd expect PSG to go deep in both domestic cup competitions.
What could affect them is the decision reached by France's highest court, approving a 75% tax on salaries exceeding one million Euros; the champions have more than 10 players in that situation, including Ibrahimovic.
Monaco are at this point not subject to such legislation, much to the chagrin of the rest of France's top division, because of their location.
Claudio Ranieri will also be hoping that Radamel Falcao is true to his word, the 50m euros striker insisting he's happy in the Principality, that's despite a curious three-week absence due to a supposed thigh strain, then missing a penalty on his return.
Falcao will represent Colombia in Brazil as long as he avoids injury, but surely he'll want to play himself into some form before then.
Award for best comeback team of the season so far has to be Bordeaux. Having been in the relegation zone in late September, they've now suffered just a single defeat in 14 games, with Nicolas Maurice-Belay and Jussie shouldering the goalscoring burden.
It's proof that if you give a manager, in this case Francois Gillot, time to turn things around, it's often better to stick than twist.
There were, however, two managerial casualties in the month before Christmas, Elie Baup paying the price for Marseille's topsy-turvy league campaign and a pointless one in the Champions League.
Jose Anigo is the controversial figure now in charge at the Stade Velodrome, while former boss Rolland Courbis has retaken the reigns at Montpellier after Jean Fernandez resigned. The southerners were champions in 2012, but their main aim two seasons on is simply to avoid relegation.
Bayern Munich are the one team in Europe who have already won non-Super Cup silverware this season, triumphing at the Club World Cup without conceding a goal, and surely the Bundesliga title will follow.
Quite simply, it's theirs to lose. Bayern are seven points clear with a game in hand, and Pep Guardiola knows a decent month off should give his charges plenty of time to recharge batteries.
Franck Ribery might just be about to pick up a gong of his own too, with the Ballon D'Or decided in January.
Twelve points is the gap from Bayern to Borussia Dortmund who have endured rather than enjoyed their season so far, sinking to fourth.
Offensively, there have been no problems - Robert Lewandowski, Marco Reus and Henrik Mkhitaryan all influential and impressive at different times, but it's at the back where they've had rotten luck.
Neven Subotic, Mats Hummels and Marcel Schmelzer were all injured in quick succession, the latter two on international duty, and Subotic won't return to action until next season.
That inevitably contributed to Dortmund going winless in the Bundesliga in December, and being overtaken by both Bayer Leverkusen and Borussia Moenchengladbach.
But Leverkusen suffered a Champions League hangover - having made the last 16, they then lost to Eintracht Frankfurt at home and Werder Bremen away. Gladbach drew at Mainz and then against Wolfsburg, and there was only one team who benefitted from all those results: Bayern.
The only fly in the ointment for Guardiola is the English threat in Europe - Manchester City have already beaten them at the Allianz, and they face Arsenal in the last 16 who also managed that feat last campaign.
But should they prevail, he has a fighting chance of bettering Jupp Heynckes triple trophy haul from 2012-13, and making Bayern the first team to successfully defend the Champions League.
The biggest surprise involving Italian teams was Juventus' failure to reach the Champions League knockout stages, but since then they have taken it out on all who have crossed their path, putting four past Sassuolo and Atalanta in Serie A, and three past Avelino in the Coppa Italia.
Domestically, Antonio Conte's team are unmatchable - Carlos Tevez and latterly Fernando Llorente have propelled them to 10 straight wins. They sit five points clear in the league, with a chance to make that eight as Roma visit in the first game of the New Year.
Atalanta were the team to breach Juve's defence for the first time in 735 minutes in Serie A, and that will be Roma's biggest challenge. But Mattia Destro could be the man to prise them open again.
The U21 international has scored three in three since his return from injury, and a chance to represent Italy's senior squad next summer will serve as further incentive.
Napoli's drop into the Europa League may prompt them to throw all their eggs into their league basket, but ten points is a big deficit to make up to Conte and co. Still, Rafa Benitez has refused to give up the fight for the Scudetto just yet, so expect a few signings in January, especially from France and England.
Defeat in the derby capped a miserable second half of 2013 for AC Milan, who sit an incredible 27 points off the lead in 13th place, but just five points above the relegation zone.
Mario Balotelli is one of the reasons the situation isn't even worse than it already is, but there have already been noises that he may depart the San Siro less than a year after his arrival. And with Stephan El Shaarawy out for two months after foot surgery, Keisuke Honda is a welcome attacking option after joining from CSKA Moscow.
Across Europe, the picture should sharpen quickly in the next month or so, especially as players are signed and sold, and teams go again on domestic and continental fronts.
It really is survival of the fittest - the winter is no place for those with a weak squad or mentality, because they will get found out.