Arsenal striker Olivier Giroud believes an early goal against Bayern Munich is critical to keeping his side's Champions League hopes alive, although he also stressed the Gunners must tighten up at the back if they are to stand any chance of reaching the quarter-finals.

GettyImagesOlivier Giroud is looking to add to his one Champions League goal this season

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Giroud has scored just once in Europe this season but with Lukas Podolski - who netted in the first leg against Bayern - out injured, the Frenchman must carry Arsenal's goalscoring burden at the Allianz Arena.

The former Montpellier man is convinced the tie is not over despite Bayern's 3-1 lead, but he is banking on a quick goal and a less porous Arsenal defence - despite the absence of first-choice goalkeeper Woijech Szczesny and right-back Bacary Sagna - in order to overturn the deficit.

"We need to score an early goal," Giroud told kicker. "In football you never know. We need to believe and stay focused. But we need to correct our bad defensive behaviour as well.

"I like to play against German teams because they are attacking all the time. There I get myself more possibilities to score."

Forward Gervinho was also optimistic ahead of the game, saying: "We just need to keep positive and give everything we have. We all know anything can happen in football. Personally, I still believe we can make it. I know it will be difficult, but I still believe in us."

Meanwhile, Bayern coach Jupp Heynckes is expecting "100% commitment in such a game" from his players, while captain Phillip Lahm predicted that "it's going to be tough for Arsenal, they have to defend well and still score three goals."