Borussia Dortmund coach Juergen Klopp hailed a "classy display" as his side powered to a 4-2 away win at Zenit St Petersburg.
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The Germans were 2-0 up inside five minutes as goals from Marco Reus and Henrikh Mkhitaryan put them in full command of the tie.
Zenit did pull a goal back through Oleg Shatov but just four minutes later Lewandowski restored Dortmund's two-goal lead. And Lewandowski struck again just two minutes after Hulk had given the Russians hope with a disputed penalty.
"We were close to an optimum performance," Klopp was quoted as saying by UEFA's website. "We showed great pressing and counter-pressing against a really talented team. My team had their moments; it was classy display, no doubt about that.
"My team are not known to lack character, so it was clear that it would be easy to motivate the boys after the 3-0 defeat at Hamburg [on Saturday] and that they would show something.
"I was well aware that they had to produce a reaction and would do so, but I had not foreseen such a great performance. We reacted perfectly to every goal we conceded. It was a good evening for us, but we are not yet through. We still have some work to do in the return leg."
Reus was instrumental in Dortmund's fast start, setting the first up for Mkhitaryan after surging into the penalty area, and it was his crisp strike that doubled the lead soon after.
"We started very well," he said. "Our tactics worked perfectly, we took an early 2-0 lead and put in a fine display, especially in the first half. In the second period we slacked off a bit and this should serve as a lesson to us for the return leg. It was very important to start well and we did just that.
"Our 2-0 advantage was deserved, as was the final result, I think. I always say it doesn't matter what the individual does, but to win as a team, and that's what we have shown today."
Zenit coach Luciano Spalletti lamented the early mistakes his side made, which meant they were playing catch up for the rest of the match. "We went out with a desire to play football," he said. "However, the two quick goals we conceded made a big imprint on the game and, you could say, decided the match. We made too many naive mistakes and were punished.
"You can't afford these kind of lapses at this level against opponents of Dortmund's calibre. If you make such ridiculous mistakes you will pay a very high price. However, we can't forget that we still continued to play football and fight for the result.
"Of course, we couldn't play with Dortmund's intensity for 90 minutes and had to make some adjustments -- Dortmund were stronger in this department. And then those mistakes.
"As for the second leg, we still have hope. We need to think what we can do on a specific day, in a specific game. We have to try to deliver a more consistent performance and avoid the mistakes we made today."