Isn’t it strange how you can sometimes look back on one particular incident -a goal,  a sending off,  a goalkeeper’s error, an injury - as the defining moment of a season’s effort. One such moment came to mind in the 42nd minute of the match at Old Trafford yesterday when Rio Ferdinand went over in a desperate bid to slide the ball away for a corner, and came up with a worried look on his face, clutching his groin.

Two minutes later, the Manchester United defender was about as mobile as a tailor’s dummy as Stuart Downing hit a low cross towards the near post and Mark Viduka dived in inches ahead of Wes Brown to head the ball past Edwin Van Der Sar for a Middlesbrough equaliser that was looking more inevitable as the game went on.

Ferdinand should not have been on the pitch at that moment. He should have been lying in the medical room, receiving vital minutes of whatever treatment they use these days to heal groin injuries. United’s army of specialist coaches should have withdrawn him immediately, sent on a replacement, re-organised, patched-up, whatever was needed to get through to half-time.

In the end, United had to settle for a point thanks to a Kieran Richardson goal in the third minute. But it wasn’t the securing of one point, but the loss of two - and the consequence of Ferdinand’s absence for at least two more weeks - that created a whole new raft of hopes and fears in London and Manchester, to say nothing of Europe.

The implications and consequences could be seismic (depending on the result of Chelsea’s visit to Newcastle) when United’s lead at the top of the Premiership will be either four points, three points, or a nerve-jangling one. But the crucial point is that United face five matches in the next 18 days, four of them away from home, and two of them in the Champions League. And they are likely to be without their entire first-choice back four for possibly one or two of these games. At this moment Gary Neville, Ferdinand, Nemanja Vidic and Patrice Evra are all on the treatment table for various injuries.

Vidic is back in training and could be back next weekend, but the danger in bringing him back too early – for the game against AC Milan on Tuesday, for instance – with Ferdinand’s departure yesterday. He came back from a similar groin strain too quickly.