The mechanisms of a football team are delicate. You win the league then add nearly 300m of talent and it doesn't necessarily mean you'll win it again, doesn't necessarily make you better, even if you're not doing something as obviously likely to cause imbalance as adding Kylian Mbappe to a Real Madrid team already stacked with left-sided attackers. Liverpool go into Sunday's home game against Arsenal having won two out of two in the Premier League and scored a healthy seven goals.