LOSC will meet Chelsea in the round of 16 later this season.
Letang said: "You can often see that between the group stages and the knockout stages, the dynamics can change.
"It will therefore be important to be part of a positive dynamic at this time. We are on two confrontations, four halves to play. For the return to be decisive and exciting, it will first be necessary to be solid at Chelsea in the first leg.
"We are going to face a team in which we already know some players.
"One thing is certain, we will sell our skin dearly and we will do everything to get through."
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