Liverpool fell to a 2-1 defeat against United as they suffered their fourth consecutive loss, putting a serious dent in their title hopes as Arsenal picked up a win against Fulham at the weekend.
Liverpool are still in the title race
The Reds suddenly look vulnerable at the back, lethargic in midfield and useless in attack despite their quality on paper which matches any attack on the planet.
Speaking to Liverpool.com via BetBrain, Heskey said his former side are still in the title race, even if things look bleak.
"At this moment in time, Liverpool look all over the place defensively. When you look at Arsenal's center-backs, they've been the best pairing in the Premier League for however long.
"They're really solid, and defending is an art that we need to bring back. We need that passion to want to defend. Gabriel, especially, wants to defend, and that is his thing. I think we're losing that a little bit.
"Liverpool are still in the Premier League title conversation, but they have thrown away an opportunity to really stake a claim that they are the ones.
"You say Arsenal but don't sleep on Manchester City as well. When the pressure is on, who can hold their nerve?
"We've seen points dropped, so you never know — but you have to put Arsenal top of the pile at this moment in time, especially with the way that they are playing and the structure that they have."
Salah's form is a huge worry
One player fans have latched on to is Mohamed Salah, who, after scoring 29 goals in 38 league games last season, has been poor. Salah has not scored in the Premier League since 14th September, and Heskey feels like his form is a massive worry.
"Salah is a worry because there is such a dramatic difference to what we're used to with him. But even last season, I don't think he particularly played well. He scored a lot of goals but I don't think he played well.
"With Mo, he is not a Sadio Mane where if you don't get the goals then you get the tenacity and the fight and the other things. With Mo, you get the goals; with Mane, you got everything.
"At this moment in time, when he isn't scoring, what is he giving you? That's the problem. With Mo and certain forwards, they always have a tendency to score at a critical point, so how long do you leave him on?
"I think the whole squad is missing Trent Alexander-Arnold. You have got to look at what he brought and his ability to create a chance as well. When it comes to that, yes they're missing him — but you can't rely on one player to bring a performance out of you."