I dont know why people think Lewandowski cant play against big teams in big games.
I'm watching him since his Lech Poznan stage (polish club he was playing in before Borussia Dortmund). He destroyed many big clubs in CL. Famous 4 goals against Real Madrid while playing for BVB in UCL semifinals, freekick goal vs Atletico Madrid while playing for Bayern, many goals vs Tottenham (including one from outside the box after taking a 180 with defender on his back), many goals vs Chelsea both home and away, beautiful header goal vs Manchester City, goal vs FC Barcelona after solo destroying Mascherano, goal and assist vs Barcelona in fameous 8-2, for FC Barcelona he scored two goals in two games vs Italy Champion Napoli both home and away, goal for Bayern against PSG, he scored a hattrick against Bayern in German Cup final while playing for BVB, he scored for BVB vs Real Madrid in 2-1 win after beautiful run while shooting perfectly near the short post against in good form Casillas. His goalscoring record against Borussia Dortmund as Bayern München player is insane. And many many more.
Nobody except Messi and Ronaldo scored more against big clubs than Lewandowski. He "just" won one UCL (as a topscorer with 15 goals) because he wasnt a Real Madrid or Prime Messi Xavi Iniesta player. Who won more UCLs as a player playing outside those two clubs while scoring more against big clubs than Lewandowski in last 15-20 years?