Ryan Giggs scored a first-minute penalty as Manchester United knocked rivals Liverpool out of the FA Cup with a 1-0 victory at Old Trafford.

19117 - Gerrard sees red as United knock out Liverpool

With Kenny Dalglish returning to Anfield to replace the departing Roy Hodgson, his side were soon on the backfoot after Daniel Agger was deemed to have brought down Dimitar Berbatov in the opening minute.

Ryan Giggs made no mistake from the penalty spot as United took an early lead. And Dalglish's day went from bad to worse when skipper Steven Gerrard was shown red for a two-footed lunge on Michael Carrick ten minutes before half-time.

With Liverpool down to ten men, United enjoyed much of the possession and the best of the chances, with Javier Hernandez coming close shortly after half-time. Berbatov held up the ball on the edge of the area, laid off to Darren Fletcher, whose cross found Hernandez, but the Mexican's header snuck just wide of the post.

Liverpool had a handful of half-chances, including Fernando Torres' effort; a well-struck shot blocked Rio Ferdinand.

Reina was quick off his line to smother a Berbatov effort after Patrice Evra deflected the ball into the path of the Bulgarian. And the Reds keeper continued to keep his side in the tie, making a string of instinctive saves as the ball ping-ponged around in the Liverpool penalty area.

United continued to search for a second goal to kill the game off, while Liverpool's chances were few and far between, but Giggs' early penalty proved to be the only difference between the two sides.