Arsenal's rather unlikely stay at the top of the Premier League continued this past weekend as they maintained their position with a 2-0 win over Fulham. Manchester City and Chelsea stayed hot on their heels by beating Cardiff and Manchester United respectively.
Three points separate the top three, reinforcing the gap between that trio and the rest that opened up over the Christmas period.
The title is a three-horse race, those horses are currently only kept apart by a nose or two and the most surprising nag at the front of this particular race is without a doubt Arsenal.
So what has been the key to this unlikely persistence at the very top of the table? Which players have really made the difference for Arsene Wenger's side? Or, to put it another way, which ones would they miss the most if they were injured?
Arguably, Arsenal's best player of the season has been Aaron Ramsey, but the Welshman has been missing for the last five games (four in the league, one against Spurs in the FA Cup), all of which they have won. So his absence clearly isn't being too keenly felt.
Mesut Ozil has, of course, provided great impetus, and his vision can be extraordinary, but his form hasn't been team-changing. Indeed, he was arguably Arsenal's worst player on Saturday, and they have several players to fill his position should he get injured.
Mathieu Flamini has brought some vocal organisation to Arsenal's midfield, but nothing that could not be replaced.
Theo Walcott's injury certainly deprives them of an 'out-ball' on the counter-attack, but his absence has given the hugely promising Serge Gnabry a chance to impress.
Olivier Giroud is perhaps a candidate for most valuable player as there is no one outstanding candidate to replace him should he become indisposed, but four goals in his last 14 games is not the record of an indispensable centre-forward.
All of these attacking players are, of course, hugely valuable to Arsenal, but it is at the other end of the pitch where their title challenge will live or die.
Arsenal currently have the joint-best (with Everton) defensive record in the Premier League, with 19 goals conceded in their 22 games. By way of comparison, at the same stage last term, they had let in 26.
This is largely due to the superb form of Laurent Koscielny and Per Mertesacker, who have formed a fine partnership in the heart of their defence.
Both men obviously have their weaknesses (Mertesacker's pace, Koscielny's predilection for a clumsy and costly error), but they have largely been excellent this season. The Frenchman in particular has a magnificent knack of just being in the right place to snuff out any danger before it really emerges, something that is easy to miss unless you're watching him closely.
“Sometimes you can say that he’s a bit too committed. But, you can never fault a guy like that. He will leave his heart on the field. Composed and quick but he’s hard with it. It’s kind of a mix of an old-fashioned and a new generation centre-back. He compliments Mertesacker.”
Only two sides have scored more than one goal against Arsenal in a Premier League game this season—Aston Villa on the opening day, which looks more and more like a surreal outlier as the days pass, and Manchester City, who have scored 63 times in the league already this term. Indeed, four of the six goals City scored against Arsenal came after Koscielny had to go off.
Remarkably, Arsenal have not lost a game that Koscielny and Mertesacker have played 90 minutes together for two years. That run has taken in 29 games, 21 of which have been victories.
It is a remarkable run, and perhaps the bigger concern for Arsenal is the reserves available to them should either/both of their key defenders become unavailable for a significant period of time.
They have not been parted for more than two games at any stage this term, and the consistency of their partnership owes a lot to this consistency in selection and playing time.
Should either be indisposed, the only other specialist centre-back Wenger has at his disposal is Thomas Vermaelen, who has not been an especially reliable option for nearly two seasons. Having the Belgian in their team would not be calamitous for Arsenal, but it would significantly weaken their back line.
Beyond him, Bacary Sagna would probably have to fill in at centre-half out of position, which clearly is not a desirable situation.
Arsenal's title challenge is very real, and it would be no surprise at this point if they managed to hold off Chelsea and Manchester City, but it depends on keeping Mertesacker and Koscielny fit and able.