This answer, if based on statistics, would result in people concluding Manchester United is better due to the fact that they have more Premiership titles than Liverpool, since Liverpool has 18 and Manchester United has 19.
Manchester united football club
Manchester United and Liverpool.
If you are asking which club, then it is Manchester United.
Manchester united won against Liverpool
They haven't the only club to achieve this are Manchester united.
Statistically speaking, Manchester United are the most successful club in English football, but Liverpool is also quite excellent.