Manchester United appear to have one hand on the Premier League title, but their poor away form could yet prove their downfall, with Arsenal and Manchester City lurking in the wings.
Away is the only danger for Manchester United
With less than a third of the Premier League season still to go, it seems apt to assess the destination of the title.
Manchester United, who have 12 games left to play, claimed three vital points last Saturday with their derby victory over Manchester City to increase their lead over their third-placed neighbours to eight.
City' title hopes seem slim (especially as they have played a game more) and Arsenal in second, just four points off the pace, look to be United's main challengers.
But one statistic will give both chasing clubs hope. United play seven of their 12 remaining games away from home and, as has been highlighted many times this season, their form on the road is mediocre.
It is not that they have lost many - the 2-1 defeat to Wolverhampton Wanderers two weeks ago was their first loss this season - but draws are hurting them.
The 2-1 victory over City means United have dropped just two points at Old Trafford. Coincidentally, United have won every home league game in which Wayne Rooney - the matchwinner against City - has scored.
However, away from home, United have only won three games.
More worrying for Sir Alex Ferguson, their manager, is their lack of away goals - just 18 in 12 games compared to 39 in 14 at home.
In fact, it is remarkable how much harder it is for Premier League teams in general to find the net away from home. Of the 20 teams in the division, 14 have a positive goal difference (ie they have scored more than they conceded) at home. United top the table with a plus 32 goal difference.
But away, just four teams have a positive goal difference, with Tottenham Hotspur in fifth with a goal difference of zero.
United are fourth with plus two, highlighting the fact that their three away victories have been by a single goal.
On top of that poor record, their fixture list is daunting. United have to go to Liverpool, Arsenal and Chelsea as well as Blackburn Rovers (where they traditionally struggle) and Newcastle United (who have beaten Liverpool and Chelsea at St James' Park).
United are currently averaging 1.4 points per game away from home, which means they stand to earn nine or 10 points from their remaining games. Even that might be ambitious given the heavyweights they have to face.
At home, they are almost unstoppable so it is realistic to suggest they should take maximum points from their five matches, or perhaps four wins and a draw with Chelsea.
By that ratio, United are on course for 80 points. Were they to win the title, it would be the lowest points total since 1998/99, which is, ironically, when they won the Treble (they also won the title with 80 points in 2000/01).
That gives Arsenal and City hope. Arsenal could therefore take the title with nine wins and a draw from their last 12 games. And they have an easier fixture list with only United and Liverpool, both at home, from the top six. City would probably need to go unbeaten though their fixture list is also relatively kind. Trips to Stamford Bridge and Anfield look tricky while Tottenham have to visit Eastlands.
Of course, football is not often predictable and equations do not determine titles.
However, it is safe to make two statements.
Firstly, if United can improve their away form, the title looks like theirs.
And secondly, if Rio Ferdinand is fit for the rest of the season, United should win the league. With the England captain alongside Nemanja Vidic at centre-back, United have conceded only once every 135 minutes this season, or 0.67 goals per game. Without him, the figure doubles.