Paris Saint-Germain (#PSG) trained on Tuesday as Mauricio #Pochettino's side begins its UEFA #ChampionsLeague campaign on Wednesday in Group A at Club Brugge, where Lionel Messi, #Neymar and Kylian #Mbappe could play together for the first time, a fearsome attacking lineup for the Belgian champion to contend with. #Messi warmed up for the game with a hat trick for Argentina in World Cup qualifying.