The Champions League returned on Tuesday with the round of 16, and two fantastic matchups featured during knockout play.

When the final whistles blew, PSG earned a dominant 4-1 away win over Barcelona—led by a Kylian Mbappe hat trick—while Liverpool got back on track vs. Leipzig with a 2-0 win. 

Below, we'll break down the winners and losers from Tuesday's action. 

Winner: Kylian Mbappe

How good is this guy?

Mbappe torched Barcelona, scoring three goals and coming close to a fourth. Absolute class. 

He's on a different level. 

Getting to see Lionel Messi, the GOAT, face off against a player like Mbappe—who has all the makings of a becoming a legend himself—is always a treat. On Tuesday, Mbappe got the better of his attacking counterpart.

Picking up four away goals and a win is one heck of an evening for PSG as they took a crucial first step toward advancing to the Champions League quarterfinals. They have Mbappe to thank for the scoring onslaught.

Loser: Sergino Dest and Barcelona's Back Line 

While PSG's attackers flourished, Barcelona's defense suffered. So poor was 20-year-old American Sergino Dest that he was subbed out in the second half. 

Granted, the rest of the back line wasn't much better, and the midfield didn't exactly help the stressed defense. There isn't room for cracks in the foundation against the elite attackers PSG possesses, and Barca paid the price for those weaknesses. 

If Barcelona has any chance to recover in this matchup, it will have to start at the back. 

Winner: Liverpool's Return to Form

The Reds have been dreadful in the Premier League of late, dropping three straight games. But they appeared to get their mojo back on Tuesday. 

They can thank Mo Salah and Sadio Mane for that:

Liverpool weren't exactly world-beaters against Leipzig, and both of their goals were the result of huge gaffes from their opponents (more on that below). But sometimes, you just need to get a win to turn things around, no matter how it comes. And Liverpool kept the clean sheet too. For a team that has been struggling, it was a much-needed result.

Loser: Leipzig's Defense

You've already seen the goals above. You know how hard to watch they are for Leipzig supporters. 

What will really stick in their craw is that this was a winnable game. Even a draw would have sufficed. Now they have to travel to Anfield, down two away goals, and find a way to erase a significant deficit against one of Europe's most dangerous clubs.

A tough evening for the Bundesliga side.