Germany winger Marco Reus has been ruled out of Borussia Dortmund's Champions League last 16, second-leg clash at home to Zenit St Petersburg on Wednesday, coach Jurgen Klopp confirmed. "Marco could not participate in team training and will unfortunately not be available tomorrow," confirmed Klopp in Tuesday's press conference. Reus was a key factor in Dortmund's 4-2 first-leg win as the 24-year-old scored early on as Borussia raced into a 2-0 lead after only five minutes, but he has struggled with a leg injury since. Zenit, who will unveil ex-Chelsea and Tottenham Hotspur coach Andre Villas-Boas as their new coach on Thursday after Luciano Spalletti's dismissal, need a minor miracle to progress to the quarter-finals. But Dortmund are taking nothing for granted. "We have created a good basis for the return leg, no more and no less," said Klopp. "We will not risk a lot, but just going out there to defend our lead would be a bit stupid as well. "We have reached our goals in the Champions League by getting out of the group stage. "Everything that happens now is a benefit for the club, but there would not be a gaping hole in our budget should we go out." With the likes of Brazil's Hulk in their ranks, Zenit will pose Dortmund problems at Borussia's Westfalenstadion even if they are winless in their three competitive matches this year. "There is no way we will underestimate them," said Germany defender Mats Hummels. "Most of the group winners did well in the away game and had more problems in the home game. "Zenit have enormous quality, especially in midfield and in attack. "We have to be vigilant, but the first-leg result puts us in a good position." Former Paris Saint-Germain midfielder and ex-Russia captain Sergei Semak will be on the touchline in Dortmund as Zenit's interim coach after Spalletti's dismissal. "Everything is possible in football, but of course we do not have much of a chance," he said. "We are up against one of the best sides in Europe, even in the world. "The result is only interesting to me if it is good enough for a win. "It is important for us to present our best and to stick together. "Only then will we have a chance to turn this around." Source: AFP