Chelsea are looking to land the knockout blow as they slug it out with second placed Tottenham in the fight for the title.
With just seven games remaining, Chelsea are looking to land the knockout blow as they slug it out with second placed Tottenham in the fight for Premier League supremacy.
Antonio Conte's side hold a seven point lead at the top, but Tottenham can temporarily trim the gap to four if they beat Bournemouth at White Hart Lane in Saturday's early kick-off.
Alonso admits that would pile the pressure back on Chelsea, who face a tricky trip to Old Trafford to face a United team fuelled by a revenge mission on Sunday.
Managed by former Chelsea boss Jose Mourinho, United have already endured a humiliating 4-0 thrashing at Chelsea in October and an acrimonious 1-0 loss on their return to Stamford Bridge in the FA Cup quarter-finals in March.
But Mourinho's fifth placed team, four points behind fourth placed Manchester City in the Champions League qualification scrap, are unbeaten in their 21 league matches since that first painful loss to Chelsea this season.
"It will be tougher this time around. They are one of the best teams in England, no doubt," Alonso said.
"It will be a very hard game, even more so after losing twice against us. They will give even more to try and beat us.
"We will have to do the same or more than before to get another win. They will be hard to beat. We will have to be ready."
Chelsea, unbeaten in their last 12 meetings with United, have won back to back matches since their shock defeat against Crystal Palace, but Tottenham remain hot on their heels.
Pochettino's side have reeled off six successive victories, sparking dreams of winning the club's first English title since 1961 and finishing above bitter rivals Arsenal for the first time since 1995.
They currently sit 14 points clear of Arsenal, but Pochettino is understandably more concerned about catching Chelsea than earning north London bragging rights.
"I think we're playing and fighting for bigger things," said Pochettino, who may hand a first start to Harry Kane since the striker's ankle injury five weeks ago.
"If we look at the bigger picture it's to try to reduce the gap with Chelsea. I think today it's not important the gap we have with Arsenal.
"The most important thing is to do our job, try to win games and try to reduce the gap with Chelsea."
Arsene Wenger and his Arsenal flops head to Middlesbrough looking to redeem themselves in the eyes of their furious fans after their shocking 3-0 defeat at lowly Crystal Palace on Monday.
Subjected to vitriolic abuse from supporters during their fifth defeat in their last eight games and labelled as "cowards" by former Liverpool defender Jamie Carragher, Wenger's sixth placed side can't afford another debacle as they try to close the seven-point gap on the top four.
Wenger, who endured calls for his resignation, has led Arsenal into the Champions League for the last 19 years, but that record is in severe danger and a defeat at the Riverside Stadium might usher the beleaguered Frenchman towards the exit.
"This isn't Arsenal in this moment in time. We thought we'd got out of this little rough patch," Gunners winger Theo Walcott said.
"Hopefully we haven't been dragged straight back into it, but judging on that performance, it looks like we have."
Second bottom Middlesbrough, six points from safety and without a win in 14 league matches, have no margin for error either as they try to avoid relegation.
City travel to Southampton, while third placed Liverpool are at West Bromwich Albion.
Bottom of the table and 10 points from safety, Sunderland will surely be doomed to the drop if they lose at home to West Ham.
Beaten by a controversial penalty from Antoine Griezmann in Atletico Madrid's 1-0 Champions League quarter-final first leg victory on Wednesday, Leicester will look to take out their frustrations on Crystal Palace.
Fixtures (1400 GMT unless stated):
Crystal Palace v Leicester, Everton v Burnley, Southampton v Manchester City (1630 GMT), Stoke v Hull, Sunderland v West Ham, Tottenham v Bournemouth (1130 GMT), Watford v Swansea
Manchester United v Chelsea (1500 GMT), West Brom v Liverpool (1230 GMT)
Middlesbrough v Arsenal (1900 GMT)