Steven Gerrard became the top visiting scorer at Old Trafford in Premier League history with two converted penalties, as Liverpool outclassed arch rivals Manchester United and won 3-0 to maintain their title hopes.
Brendan Rodgers's men, who have now won five league games in a row, started well today, with Daniel Sturridge fluffing his lines with two shots in the first 20 minutes.
Down the other end, United were doing very little creatively and had only one decent opening in the first half when Rafael da Silva crossed for Wayne Rooney, whose instinctive shot was parried out by Simon Mignolet.
The deadlock was broken in the 34th minute when Gerrard side-footed home from 12 yards after Rafael had misjudged a crossfield pass and handled when Luis Suarez tried to knock the ball past him.
Having been booked moments earlier, the Brazilian right-back was fortunate not to be cautioned again and sent off.
Just seconds after the restart, Liverpool had their second penalty when Phil Jones barged into Joe Allen. De Gea guessed correctly this time, but he could do nothing about Gerrard's penalty that nestled right in the corner.
United couldn't muster any real pressure and were being restricted to hopeful efforts, with Marouane Fellaini slicing wide from a good opening midway through the second half.
Gerrard almost had his hat-trick from open play with a deflected shot in the 75th minute, before Van Persie headed wide as United broke down the other end.
The Liverpool skipper then had a golden opportunity for a memorable Old Trafford hat-trick, as Liverpool were awarded a third penalty when Sturridge fell under the challenge of Nemanja Vidic.
Replays showed that there was little, if any, contact but referee Mark Clattenburg was convinced and also sent off Vidic with a second yellow card.
Gerrard went the other way with the penalty, fooling De Gea but not finding the corner as the ball came back off the foot of the post.
Suarez sealed the win six minutes from time by tucking home from inside the box after he had been denied by a spectacular De Gea save moments earlier.
Three points move Liverpool up into second place, four points shy of league leaders Chelsea but with a game in hand.
David Moyes's United remain seventh, five points adrift of Tottenham Hotspur in fifth.