Yeah but the game changes completely upon that penalty decision. They had to guard against the Liverpool counter from that point onwards rather than being able to play their own counter style.
This is it though, it’s so easy to look back afterwards and say ‘yeah but they were poor afterwards’. Big decisions change the outcome of games and Liverpool continue to get the vast majority of the major decisions in games going their way to their benefit nearly all the time. Over the course of a season that adds up, and in cup competitions that leads to wins.