Changes are needed by every player because in their first Premier League match, they seemed to have lost their best form. The coach must evaluate their failure to penetrate the opposing defense so that when they face similar problems in future matches, they have options. In the Champions League, Chelsea will certainly face a much more evenly matched opponent, so they need a player who can make a difference when their front line is struggling to score goals. This is the kind of player Chelsea needs when they are having trouble scoring goals, so matches don't end in draws or losses.
Chelsea needs a more agile midfield that can create passes and a more solid defense that can withstand attacks. Chelsea only needs a little polish on their attack, so the bigger focus is on their defense and midfield so that their attack can be sharper and better than last season. I still see Chelsea as a good team, even though in their first match of the season in the domestic league they suffered a goalless draw, despite having a few chances, which were wasted. Therefore, the Chelsea coach needs to evaluate this so they can truly be strong in this season's Champions League.