Nemanja Vidic demands Manchester United fix their leaking defence

Nemanja Vidic says Manchester United's once-invincible defence is crumbling after the 2-2 Champions League draw against Porto and warned it must be fixed quickly.

United's back four were hailed as the best in the world when goalkeeper Edwin van der Sar went a record 1,311 minutes in the Premier League without conceding a goal earlier in the season. But not any more.

The way Mariano Gonzalez sneaked in unmarked to score a late equaliser at Old Trafford last night typified how Sir Alex Ferguson's side have struggled lately.

It wiped out Carlos Tevez's 85th-minute goal that had looked set to win the quarter-final first-leg tie despite a nervous display in which Porto went ahead after four minutes only for Wayne Rooney to equalise.

United have now conceded 10 goals in their last four matches, including a 4-1 defeat at home to Liverpool, and Vidic says the situation cannot continue.

The Serbian, who partnered Jonny Evans in the continued absence of Rio Ferdinand through injury, said: "It's very disappointing to lose a goal at the end like that when you are winning 2-1.

"If you look at the last four games then obviously we haven't played like we did in the 10 games before that. We have conceded too many.