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DORTMUND, Germany, March 19 (Reuters) - Borussia Dortmund reached the Champions League quarter-finals for the second successive season on Wednesday, surviving a 2-1 second-leg defeat by a spirited Zenit St Petersburg to go through 5-4 on aggregate.
Dortmund, last year's runners-up who won 4-2 in Russia in the first leg, were far from their best and fell a goal behind when Hulk thundered Zenit into the lead with an unstoppable long-range effort in the 16th minute.
Dortmund captain Sebastian Kehl settled the hosts' nerves when he headed in the equaliser in the 38th minute before the visitors retook the lead in the 72nd through substitute Jose Rondon's diving header.
Dortmund held on in a scrappy finale and the 2-1 defeat was enough to send them into the last eight as the second German team along with Bayern Munich.
They were dealt a blow however as defender Marcel Schmelzer suffered a suspected groin injury that could see him join their already long injury list.
"Zenit had to come forward and they have such quality in attack," Kehl told reporters. "We did not have our best match today but we can leave here with a big smile on our face."
Yet Kehl said he was unhappy with the atmosphere in the stadium and questioned what team mate Kevin Grosskreutz called "moaning fans" who had come seemingly expecting a rout.
"I found this atmosphere in the stadium a bit depressing. Maybe they wanted to see a 6-1 win but that does not happen every day," he said.
"We have had a lot of injuries this season but this result shows we are well prepared. So the season is not that bad as some make it out to be."
In a lively start to the game, Dortmund, who had won eight of their last nine Champions League home matches, came close in the fifth minute but Pierre-Emerick Aubameyang's header sailed narrowly wide.
Zenit, who sacked coach Luciano Spalletti after a run of one win in 12 competitive matches and will be managed by Andre Villas-Boas from Thursday, responded a minute later with an Axel Witsel shot that forced keeper Weidenfeller to save at full-stretch.
Brazil international Hulk did better with a thundering left-foot drive from 25 metres that left Germany international Weidenfeller with no chance and gave caretaker coach Sergei Semak something to smile about in his last match in charge.
"They were fresh, they took risks because they had to and we had to put a huge amount of work into it," said Dortmund coach Juergen Klopp.
"We did not communicate at times. There was nervousness, you could see it. That is why we deserved to go through. The players battled extremely hard."
Dortmund, missing the pace of Reus in attack, were dealt a further blow when striker Robert Lewandowski was booked for a hand ball, ruling him out through suspension from the quarter-final first leg.
It took time for them to recover but not before Oleg Shatov threatened Dortmund again with a low drive.
It was the Germans who scored before the break, however, with Kehl rising high above defender Domenico Criscito to head in a perfect Marcel Schmelzer cross from the left.
The goal meant Zenit needed another three to advance and the pressure told in the second half with Dortmund controlling the tempo.
"It was a huge job for us to come here and score three goals and unfortunately we could not do it," said Zenit coach Semak. "I must congratulate my team on a good performance, the boys did the best they could do."
Zenit struck against the run of play when Rondon silenced the home crowd in the 72nd minute but it was too little too late as the Russian side crashed out after only their second win in the competition this season. (Reporting by Karolos Grohmann, editing by Ed Osmond and Toby Davis)