Manchester United's record 11th consecutive clean sheet in the Premier League is a great achievement, but I am not sure I would crown them the best defence of all-time.
I suppose records speak for themselves, but I think we need to look at how football has changed over the years.
It used to be the case that defences were constantly tested, regardless of their league position, and you had very few nil-nil draws. Teams are now so negative away from home that you do not see defences come under as much pressure.
United have come under fire for struggling to break teams down when they get men behind the ball - but the flip-side is that they keep a lot of clean sheets because their opponents always have nine or 10 men behind the ball.
Five, 10 or 15 years ago, teams would go to Old Trafford and have a real go at United, and they nearly all played a 4-4-2 formation - nowadays they are lucky to have more than a couple of shots on goal.
The game has changed, and we need to look at the proper context before we start comparing teams from different eras.
If you go further back, you get to the era when teams had five forwards and games finished 6-4 or whatever. You wouldn't necessarily say Dixie Dean was the best player of all-time because he scored 60 goals in a season, and I feel the same way about comparing defensive records.
It is particularly interesting that United have achieved this record with Patrice Evra and Rio Ferdinand missing for most of the games, and with no recognised first-choice right-back.
I like Jonny Evans, who has stood in for Ferdinand, but I think if you put him, Nemanja Vidic, John O'Shea and Rafael da Silva into any defence outside the top four they would concede goals.
That is because teams would have a go at them and try to exploit their weaknesses. Against United - particularly at Old Trafford - teams are so scared of getting hit on the counter-attack that they dare not push players forward.
In a sense, this defensive record is a tribute to the quality of the team's attack. If the likes of Rooney, Tevez and Ronaldo weren't as devastating on the break, teams might have more of a go at them.
I wouldn't like to name the best defenders that have played at United in recent years, but I can certainly tell you the best goalkeeper - Peter Schmeichel.
Edwin van der Sar is good, but he is not in Schmeichs's league and he has been lucky to come into a team where he is not called into action very often.
Peter might have conceded more goals, but I don't think anyone in their right mind would rather have Van der Sar between the sticks.
It is only a couple of years since Chelsea set the record and we were hailing Petr Cech, John Terry and Ricardo Carvalho as the best in the world.
The fact that United have broken the record so soon says as much about the kind of football we see nowadays as it does about the quality of their defence.