McManaman, speaking at the launch of the Setanta TV Sports channels, said: "The holy grail of the Liverpool fans seems to be the Premier League.
"They have won the Champions League but everyone is hankering on about the Premier League.
"As much as everybody else has gone out and strengthened and I still think United will buy more players, the fact is there was a 21-point difference between Manchester United and Liverpool last season - it is a big gap.
"Manchester United have bought players for the Champions League. Their second leg defeat to AC Milan last season was down to tired legs and a lack of bodies. Alex Ferguson doesn't want that to happen again.
"But it is not as if they have bought five players who are going to go straight into the starting 11.
"They want to be strong in all competitions right up until the end, that's why they have bought these players. I think they have bought for all four competitions."