If you are so sure that Liverpool will win then you should place a good amount of money on them since the odds is around 3.3-3.4
You will have a nice profit if the match will end as what you expect but you should not force yourself to bet more than what you cant afford to lose.
I wont underestimate City as they are going to play on their own home although there will be no 12th players (fans) but being a home team is still an advantage.
I think double chance Draw or Liverpool is a good choice with nice odds (around 1.