Barcelona (Spain), Sep 8 (IANS): Robert Lewandowski scored a hat-trick as FC Barcelona enjoyed a comfortable start to their UEFA Champions League campaign with a 5-1 win at home to Viktoria Plzen.

Coach Xavi Hernandez made several changes to the side he had been using in La Liga, with Franck Kessie given a start and rewarding the coach with the opening goal, finishing well after Jules Kounde's cushioned header in the 13th minute on Wednesday night.

Lewandowski continued his excellent start at the Camp Nou in the 34th minute, when he took two touches before driving home following a run from Sergi Roberto.

The visitors pulled a goal back against the run of play when Jan Sykora scored from close range, but Lewandowski's second of the match in first-half injury time restored Barca's two-goal advantage.

Lewandowski completed his hat-trick with a shot from the edge of the area after an assist from Ferran Torres, who then added a fifth himself after a lobbed pass from Ousmane Dembele, reports Xinhua.

All three goals in Atletico Madrid's 2-1 win at home to Porto came in injury time in an incredible finish to the match in the Metropolitano Stadium.

Mario Hermoso went from hero to villain inside just three minutes, before Antoine Griezmann sealed the win with virtually the last touch of the match.

Atletico were outplayed at times by Porto but looked to be on their way to victory when Hermoso's deflected shot looped into the net in the 91st minute, but two minutes later the defender was penalized for handball, allowing Mateus Uribe to level from the penalty spot after a VAR check.

There were still five minutes to be played and Griezmann won the game in the 110th minute when he was unmarked at the far post to head home a goal nobody could have expected from a corner.