Over the last three decades Manchester United have always been able to boast at least one commanding and accomplished central defender.
In the late '80s, when United had slumped to the middle of the First Division, they still had the imperious Paul McGrath marshalling their defence.
When Sir Alex Ferguson decided to move the troublesome Irishman on, he was replaced first by Steve Bruce and then by Gary Pallister.
For six years Bruce and Pallister formed a partnership that would return United to the summit of English football with three Premier League title wins.
Bruce was the side’s captain and leader, always a threat from corners. He once even scored 19 goals in a single season (1990-91). His dogged brilliance and positional sense compensated for a lack of pace, while the languid Pallister was a more elegant performer and was rarely beaten in the air or on the ground.
In the summer of 1998 when Pallister returned to his native North East, United broke the world record transfer fee for a defender by paying PSV Eindhoven £10.75 million for Jaap Stam.
Accompanied by Ronny Johnsen, another world-class talent, Stam would win the Champions League in his first season and finish each of his three seasons at Old Trafford as a Premier League champion.
In 2002 United were not afraid to break their transfer record by paying £29 million for Rio Ferdinand, who would evolve into one of England’s greatest-ever defenders.
In January 2006 Ferdinand was joined by Serbian international Nemanja Vidic, and together they would form arguably United’s best-ever central defensive partnership, which would deliver five Premier League titles and three trips to the Champions League final, winning it once in 2008.
This summer both Vidic and Ferdinand finally left Old Trafford, and stripped of their combined experience of over 900 games for the club, it was natural to assume players of equal talent would soon replace them.
United had known since the beginning of the year the pair would be leaving, and yet two days after the start of the season United have so far refused to enter the transfer market to address their clearly weakened back line.
At this moment, for the first time in more then three decades, United are without an experienced or world-class central defender.
On Saturday this meant United took to the field for their opening game of the new season against Swansea City at Old Trafford with their weakest and most undistinguished defence in living memory.
The back five consisted of Jesse Lingard and Tyler Blackett making their debuts alongside Chris Smalling and Phil Jones, both still emerging players themselves, and Ashley Young in the unusual role as a wing back.
Unsurprisingly such inexperience could not be overcome, and United went down to their first home defeat on the opening day of the season since 1972.
United have Luke Shaw and Jonny Evans to return from injury, but that is it. There are no experienced defenders on the books ready to rescue them.
There are still two weeks remaining until the transfer window closes on September 1, and it is clear United need to bring in new recruits.
United do not need any more squad players or players with mere potential; they need at least one, possibly two world-class central defenders who will make an immediate impact.
United need to move to secure players of the calibre of Borussia Dortmund’s World Cup winner Mats Hummels or Serie A’s best defender in Roma’s Mehdi Benatia.
Time is running out, and United need to restore a world-class defender to their back line.