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And Goretzka was surprised by his team-mate's effectiveness against the Blues after seeing him prepare for the game.
"He's actually a phenomenon," Goretzka toldSport1.
"When I sawhow he trained last week, I thought to myself: 'Should I talk to him about why he's not running?'But he only said: 'Keep calm! Saturday is important.'"
He continued:"Winning the treble is our goal in the end, but it's a very special competition. It has a bit of the character of aEuropean Championship or World Cup. But we're really hot and looking forward to the trip."
Lewandowski has scored 13 times in the Champions League this season and is four short of Cristiano Ronaldo's record for most goals in a single campaign.
But the 31-year-old says he is not thinking about individual records as they turn their attention to the quarter-final clash against Barcelona.
"The record is not a goal. We only have one knockout game now and we have to play really well as a team. The most important thing is that we win and play the next round," he said.
"We have to show as a team that we are better and that we want to get to the semi-finals.
"Barcelona are always dangerous. They are always dangerous and always play great football.
"We have to from the first minute watch out and show our quality. This is just one game and the better team will play in the next round.