PSG were dominant so do not need to change tactics. They can win the game in England if the play the same way. PSG deserved to win they had 27 shots on target. Liverpool had 2 but scored against the run of play.
Even if PSG doesn't need to change their tactics, they must adjust it with the next tactics applied by Liverpool. I'm very sure Liverpool will change their tactics because it looks very badly today. It was just lucky that Liverpool still could score 1 goal. In the next Leg, Liverpool may not be lucky again if they apply the same tactics. However, for PSG, I think their need to give special exercises for their attackers to improve their shot accuracy. Today, PSG attackers wasted too many chances for scoring goals.
The most changes between the two teams happened because Liverpool team performed poorly. Because Liverpool team's luck is very good that's why they succeeded in one attack out of two attacks. And Liverpool team's defenders were under a lot of pressure during the whole match, only because PSG team's attack section did not have experienced players in this match Liverpool team was able to win this match.
PSG team's players tried hard for a long time but they could not bring any change in their luck and scoreboard. I think this was the worst time for PSG team.