Manchester United's grasp on their Premiership title is proving as shaky as their brittle defence.
Since Rio Ferdinand began his eight-month ban, United's defence has leaked eight goals in three league games.
In all honesty, it could have been more against three opponents - Southampton, Everton and Middlesbrough - all in the bottom half of the table.
Gary Neville dropped out of the side which conceded three goals in that dramatic second half against Everton at Goodison Park last Saturday.
But, two goals conceded in the first 38 minutes, prompted United manager Sir Alex Ferguson into making another defensive change at half time with Phil Neville replacing the out-of-sorts Wes Brown.
Carling Cup finalists Boro exploited United's defensive deficiency's to perfection with the quick breaking Gaizka Mendieta, Boudewijn Zenden and especially Juninho quick to support lone striker Joseph-Desire Job.
The fact that Juninho was the smallest man on the pitch did not stop the Brazilian scoring with two headers.
In the 34th minute, a blistering 30-yard shot from Frank Queudrue was touched onto the bar by United goalkeeper Tim Howard.
Howard failed to gather the ball and United's defenders stood like admiring statues as Juninho stooped to head home the rebound.
Four minutes later, United's lamentable defending saw them go 2-0 down.
Stewart Downing crossed from the right and Juninho nodded the ball in at the near post from eight yards out.
United were thrown a lifeline two minutes into first-half injury time.
Paul Scholes and Ryan Giggs worked the ball through the middle of the Boro defence and, as Louis Saha shaped to control the ball for a shot, Ruud van Nistelrooy darted in to lash his right-foot shot into the net from six yards.
United went for the Boro jugular and levelled the scores in the 63rd minute when van Nistelrooy headed on Phil Neville's cross from the right and Giggs bundled the ball in left footed six yards out on the far post.
The magnificent Gareth Southgate blocked a goalbound effort from John O'Shea as United pressed for their third goal.
But, as they charged forward, that creaky defensive gate was left open yet again ten minutes from time.
Job collected a pass from substitute Stuart Parnaby, turned Phil Neville on the left edge of the United box, and buried his left-foot shot in the far corner of the net.
There was one last gasp from the Reds when substitute Diego Forlan headed a Saha cross onto the bar in the fourth minute of injury time but life was extinguished seconds later for the sickly United defence.