Impressive first half performance by Liverpool, there's a couple of things that grabbed my attention. First, that Salah had a very easy time finding spaces due to the big distance between Sane and Laporte. Very surprising that Guardiola didnt prepare better for Salah, especially considering that Laporte isnt even a natural fullback, it makes no sense that he had no support on that flank.
Second, Liverpool's pressing was somehow even more effective than in the previous game between the two teams. If you watch the buildup to the 2nd and 3rd Liverpool goals you will notice the same pattern, Liverpool tightened the spaces in midfield, got the ball back, and with City out of position due to their weird formation, Liverpool had an easy time getting the ball forward.
Speaking of which, City's formation was a massive failure. A weird 4-2-3-1 or 3-2-4-1 hybrid of sorts in which Walker was forced to push up (which was a liability when City lost possession), with Gündogan as some sort of makeshift winger, while De Bruyne dropped deeper and played next to Fernandinho... Seemed like an attempt by Guardiola to bypass Liverpool's pressure by having De Bruyne play from the back, but the fact that it required some players to play out of position, and also constantly change the formation from attack to defense meant City was a total disaster during the first half.