Five things we learned from Champions League: PSG's depth too much for Barca; Rio Ngumoha key for Liverpool?

While Paris Saint-Germain secured an important win over Barcelona, several key players made a case for themselves in other matches across Europe Even at the earliest junctures of the season, the UEFA Champions League is a showcase for the world's best players on its very best days. Tuesday was no exception, this time providing a platform for a batch of players that usually play supporting roles to their headline-stealing teammates. Paris Saint-Germain once again earned the distinction of being the Champions League's headliners, outdoing Barcelona in a 4-2 win that was the latest in a string of instant classics between two of Europe's most entertaining teams. The back-to-back champions surged to victory while relying on a wide range of talent, though they were hardly the only ones to showcase their depth.

Liverpool's 4-3 win over Villarreal came courtesy of 18-year-old Rio Ngumoha, while Manchester City called upon Phil Foden in a 5-1 win over AEK Athens. Depth will naturally be a theme of the Champions League campaign as it progresses, long seasons in store for title contenders and the teams destined for early exits. Tuesday's games offered an early glimpse at how several teams might fare down the stretch if things go according to plan – and who might throw a wrench in their plans, should the knockout phase draw