Olivier Giroud told Chelsea to believe in an "almost impossible" comeback against Bayern Munich in the Champions League last 16.

The Premier League side suffered a 3-0 loss in the first leg of the tie at Stamford Bridge on Tuesday, leaving them on the brink of elimination.

However, Giroud said Chelsea – who had Marcos Alonso sent off in the second half – needed to take belief into the second leg in Munich on March 18.

"It's going to be almost impossible but we need to go there with belief and to believe that we are going to score. You never know, you know," the forward said.

"They scored three goals here and if we score three and don't concede, you know. I'm not joking.

"We have nothing to lose and we're going to play our game with more."

Former Arsenal attacker Serge Gnabry netted a brace for Bayern, while Robert Lewandowski sealed the win.

Giroud, a former team-mate of Gnabry's, was happy for the attacker, who made just 18 appearances in all competitions for Arsenal.

"I played with him at Arsenal. At 16, he was not mature enough but obviously at 16 nobody is," he said.

"But the way he improved is amazing and he is doing so well since the last two or three years now. I'm happy for him because he deserves it and he's a good guy who has worked a lot.

"He's been very good tonight also, so it's good for him and we need to bounce back on Saturday.

"It's very disappointing today, but I understand sometimes you try but they were too good for us."