Paris Saint-Germain made a statement in the first leg of the UEFA Champions League Round of 16 tie against Barcelona with a 4-1 win at the Nou Camp, which put them in pole position to qualify for the quarterfinals.Kylian Mbappe scored a hat-trick to put Barcelona to the sword, leaving Mauricio Pochettino's side in full command of the tie.Lionel Messi scored a penalty in the first half to give Barcelona the lead in that game, but that was all the joy that the Blaugrana managed to get throughout the game.Mbappe equalized in the 32nd minute and PSG took complete control of the game from there. The Frenchman added a second midway through the second half before Moise Kean scored just five minutes later.The 22-year-old superstar then completed his hat-trick five minutes from time, as Paris Saint-German put to bed the demons from 2017, when they lost 6-1 in Barcelona to bow out of the competition.Mbappe Scores A Hat Trick For PSG Knocking Out Barcelona! #mbappe #ChampionsLeague pic.twitter.com/d3J5WNMjKo— Serretiant (@Serretiant) February 17, 2021Paris Saint-Germain destroy Barcelona at the Nou CampWith Lionel Messi's contract situation still up in the air, we might well have witnessed the legendary Argentine's last UEFA Champions League game at the legendary ground.In a way, it was also symbolic of Barcelona's struggles this season that they have lost their last two home games in the Champions League and conceded a total of seven goals in that period.3 - Barcelona's 4-1 defeat to PSG was their second home defeat by three or more goals this season (also 0-3 vs Juventus) - as many as they suffered in their previous 20 seasons combined in all competitions. Decline. pic.twitter.com/LuRcQL2yS3— OptaJoe (@OptaJoe) February 16, 2021📊[OPTA] | Barcelona have lost consecutive home games (0-3 vs Juventus 🇮🇹 and 1-4 vs PSG 🇫🇷) in a single European competition season for the first time ever. Unfocused. pic.twitter.com/qi8Xl4QSSA— Barca Times Stats (@Stats_BT) February 17, 2021📉 - Barcelona have conceded 1️⃣2️⃣ goals in their last 2 KO matches in the Champions League.8-2 vs FC Bayern4-1 vs PSG#FCBPSG #UCL— Gracenote Live (@GracenoteLive) February 16, 2021While there is talk of a symbolic passing of the baton from Messi to Mbappe, the Frenchman put on a show last night. It is also fair to say that Mbappe does love playing against teams that have Messi in them.Kylian Mbappé has now played against Lionel Messi twice in his career, both in knockout games:⚽️⚽️ France 4-3 Argentina⚽️⚽️⚽️ Barcelona 1-4 PSGHe's scored five goals. pic.twitter.com/OUSspJOdEV— Squawka Football (@Squawka) February 16, 20211 - Kylian Mbappé is the 1st player to score a hat trick v Barcelona in the Champions League knockout phase. Galactic ☄️. @PSG_English pic.twitter.com/qfbiWuNTke— OptaJean (@OptaJean) February 16, 2021🇫🇷 After his hat-trick against Barcelona, this is Kylian Mbappé's record in the Champions League:✅ 41 Games⚽️ 24 Goals🅰️ 17 GamesThe 22 year-old PSG forward is averaging one goal involvement per game in Europe's elite competition!😲#UCL #FCBPSG #BarcaPsg pic.twitter.com/NRpudK31Gv— Soccer Manager Games (@SoccerManager) February 16, 2021There was also another blast from the past that an alert Twitter user pointed out.Barcelona should stop beating Alaves before playing PSG pic.twitter.com/R0QtMv4oai— Bobbyy. (@floydmontana0) February 16, 2021For Pochettino, who had coached Espanyol before heading to England, it was a lift-off for him in his PSG career. So far, his tenure has been marred by injuries to key players, which has left them a point off the top of the Ligue 1 standings.Before tonight, Mauricio Pochettino had faced Barcelona 11 times in his managerial career with his only win coming at Camp Nou during their 2008-09 treble-winning season...His PSG side just became the first French team to beat Barça at Camp Nou in the Champions League. #UCL pic.twitter.com/1tWTPF7aoF— William Hill (@WilliamHill) February 16, 2021Barcelona being poor shouldn't take away from how good Paris Saint-Germain really were. However, the Blaugrana were plagued by their key players not stepping up to the plate. Substitute Francisco Trincao provided a spark, but it was way too late by the time he came on to the pitch.🇵🇹 Trincao completed 4 dribbles in 13 minutes played as a substitute against PSG.The rest of Barcelona combined for 5 dribbles all game😳 pic.twitter.com/c96yDcVOUG— Matchday365 ⚽️ (@Matchday365) February 16, 2021It hasn't been the best of times to be a Barcelona fan, with the club now almost certain to not win a trophy this season.Barcelona since July 2020:- Lost La Liga title to Madrid- Lost 8-2 vs. Bayern- Kept Messi against his wishes- Worst start to season in 32 years- Lost to Bilbao in Super Cup- 5 points behind Atletico, who have two games in hand- Down 1-4 to PSG in the first leg Hmmmm pic.twitter.com/JMckteMris— #ALFREDO🇬🇧🇬🇭 (@BoadiAsemah) February 16, 2021Barcelona are 2-0 down against Sevilla in the semifinal of the Copa Del Rey, so they face another huge challenge to get to that final and are hanging by a thread in Europe as well.