While in-form United hope to mount a challenge for their first English title since 2013, Liverpool, already seven points behind their second-placed rivals, are battling to stay relevant after an inconsistent start.

Liverpool's Philippe Coutinho, second from right, celebrates scoring his side's first goal of the game with teammates during the game against Newcastle United during the English Premier League soccer match at St James' Park, Newcastle, England, Sunday, Oct. 1, 2017
Liverpool's Philippe Coutinho, second from right, celebrates scoring his side's first goal of the game with teammates during the game against Newcastle United during the English Premier League soccer match at St James' Park, Newcastle, England, Sunday, Oct. 1, 2017 (AP)

Jose Mourinho's unbeaten Manchester United face the biggest test yet of their title credentials when they visit Liverpool at Anfield on Saturday – a fixture that always has a little extra spice.

United are second in the Premier League, level on 19 points with neighbours Manchester City, but so far Mourinho's side have yet to face any of last season's top five.

Six wins from their opening seven games, with 21 goals scored and only two conceded, have raised expectations at Old Trafford, but the coming weeks should give a stronger indication of just how ready United are for a real push for the title.

Spurs visit Old Trafford on October 28 and then a week later United travel to Stamford Bridge to take on defending champions Chelsea, Mourinho's former club.

The North West derby has always had an extra edge and even though the lack of local players for both clubs could take away some of the needle from the game, the passion from the stands continues to create a special atmosphere.

"Anfield away is the ultimate test, mentally and physically with the intensity," former United captain Gary Neville told Sky Sports.

"There’s obviously less homegrown talent but the atmosphere will be brilliant and it is a game which you dare not lose as a player."

Particular focus will be on United's $98 million Belgian striker Romelu Lukaku, who has been in prolific form, scoring in 12 of his last 13 games for club and country.

The powerful forward joined United from Everton during the close-season and has been an instant success – but there are still some who question whether he can be just as effective against better opponents.

While Lukaku – and United – will want to prove that they are the real deal, Liverpool badly need to kick-start their campaign after a shaky beginning.

Juergen Klopp's side have taken just five points from their last four games, leaving them seven points behind the Manchester clubs.

The exciting attacking talent in the team, despite the loss to injury of Sadio Mane who is out for six weeks with a hamstring injury, should test the United defence that has had a relatively comfortable campaign so far.

Former Liverpool striker and manager Kenny Dalglish expects Mourinho to protect his defence with a cautious approach, similar to how they played in last season's 1-1 draw on Merseyside.

"Last year, when United came to Liverpool, Jose Mourinho parked the bus. But it wasn’t just the one bus, I think it was a couple of double deckers he put there," said Dalglish.

Source: Reuters