Steven Gerrard's error gifted Arsenal a 2-1 Premiership victory over 10-man Liverpool on Sunday, while Manchester United and Charlton also won.
Reds captain Gerrard allowed Thierry Henry to give the Gunners all three points in a dramatic finish at Highbury in the evening clash.
Henry had put the home side ahead in the 21st minute but Luis Garcia appeared to have earned Liverpool a precious point with a headed equaliser 14 minutes from time.
But just two minutes after Xabi Alonso had been harshly sent off for a second bookable offence, Gerrard's back pass was intercepted by Henry, who rounded Reina to score his second of the game in the 83rd minute.
Liverpool are now five points adrift in the race for second place after Wayne Rooney's first-half double proved enough to give Manchester United a richly-deserved 2-0 triumph over Newcastle at Old Trafford.
Rooney took advantage of a Peter Ramage blunder to put the hosts in front, then doubled United's lead with a blistering finish not long afterwards.
The only wonder was United did not add to their tally during a one-sided encounter but Rooney wasted the best of a succession of golden opportunities when he rounded Shay Given and put his shot against a post.
Darren Bent's double strike earned Charlton a 2-1 victory over Middlesbrough at The Valley.
Mark Viduka looked to have snatched a point when he cancelled out the England striker's second-half strike with nine minutes to go following a superb piece of skill.
However, Bent swept in his 19th goal of the season with just three minutes to go as the Addicks ended a run of three goalless draws.
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