Liverpool striker Fernando Torres marked his first start since January 13 by scoring the winner in an ill-tempered 2-1 victory over Blackburn at Anfield.
The Spanish international hit his 13th goal in 17 Premier League appearances just before half-time, having missed five weeks at the start of the year after a knee operation.
Liverpool had gone ahead midway through the half through Steven Gerrard only for Jamie Carragher's handball to allow Keith Andrews to equalise from the penalty spot five minutes before the interval.
With fellow top-four rivals Tottenham and Manchester City both winning this weekend it was imperative Rafael Benitez's side maintain the pressure and they ground out a win against combative opponents.
Fifth-placed City remain one point ahead of Liverpool after beating Chelsea 4-2 at Stamford Bridge on Saturday, while Spurs hold fourth place on goal difference after their 2-1 win over Everton on Sunday.
Roman Pavlyuchenko scored his sixth goal in four games when he netted the opener at White Hart Lane before Luka Modric doubled Tottenham's lead with a fine second against David Moyes' men.
Spurs had to survive a second-half comeback from Everton, who scored through Ayegbeni Yakubu and then saw substitute Landon Donovan miss an open goal.
Elsewhere, Fulham goalkeeper Mark Schwarzer denied struggling Sunderland a first Premier League victory in 14 attempts, to leave the Black Cats hovering precariously above the drop zone.
The Australia international kept out Darren Bent's first-half free-kick and then blocked Alan Hutton's left-foot effort after the break to ensure the game ended goalless.
The point lifted Sunderland three clear of the drop zone, but there is little doubt that Roy Hodgson will have been the happier manager.
Fulham extended its unbeaten run in all competitions to eight games, three days after it secured its passage to the last 16 in the Europa League.