London: Something will have to give when in-form Liverpool and bitter rivals Manchester United clash in one of the Premier League`s showcase fixtures at Anfield on Sunday.
Liverpool have won their last five league games and eight of their last nine and meet a United side who have won their last three league games and are undefeated in 17 of their last 19.
United produced their best performance of the season to beat Tottenham Hotspur 3-0 last Sunday and have kept a clean sheet in their last three league games, despite the endless negative analysis of their style under coach Louis van Gaal.
While leaders Chelsea, who visit Hull City on Sunday, and second-placed Manchester City, who host West Bromwich Albion on Saturday, remain the main title contenders, neither can afford more slip-ups with Liverpool, United and Arsenal on their tails.
City can now join Chelsea and Arsenal in concentrating on the title after exiting the Champions League at the first knockout stage, although Arsenal are still hoping to retain the FA Cup.
Like Liverpool and United, Arsenal are on a roll domestically having won their last five league matches and 15 of their last 18 in all competitions and could well extend that run at mediocre Newcastle United.
Chelsea are top on 64 points -- and have a game in hand on all the others -- followed by City (58), Arsenal (57), United (56) and Liverpool (54).
Although Chelsea remain overwhelming favourites to win the title -- something coach Jose Mourinho declared last week they will do -- the race for a top-four finish is coming to the boil with little margin for error at Anfield for Liverpool or United.
Liverpool have improved after a sluggish start and manager Brendan Rodgers praised his side for a "remarkable" second-half performance in the 1-0 win at his former club Swansea City on Monday in which they kept a sixth successive clean sheet away.
Afterwards Rodgers said he was relishing their improved form and rise up the table.
"For the last three months we have been in outstanding form but we just have to keep working because we know what our objective is and are looking forward to climbing into the top four."
While Van Gaal will be hoping to keep United among the leading quartet this weekend, another Dutch coach will make his league debut.
Dick Advocaat, who replaced Gus Poyet at Sunderland on Monday, will aim to halt their slump to within one point of the relegation zone in his first match in charge at West Ham United.