Chelsea have 50% of making it through to the next round of the Champions League, interim manager Guus Hiddink said on Monday.
The Blues face Paris Saint-Germain tonight at the Parc des Princes with captain John Terry out of action with a hamstring injury.
New signing Alexandre Pato will also not be involved with midfielder Nemanja Matic banned.
"It's 50-50," Hiddink told reporters.
"If you see where we are now and where PSG are now, they are building a very strong team and dominating the French league completely. They are 24 points ahead, and are focusing to get this Champions League.
"A big club has to win the Champions League.
"The league didn't start well for us this year, and we've had some recovery from December up to now, but we're desperate to get into the next round of the Champions League.
"It's a big test for us to get into the next round and I hope we can do something to swing it to our advantage.'
"You have so many good teams, though, it's very difficult. It's beautiful to win a big, big cup.
"We are growing. Everyone knows the situation of Chelsea in recent months and weeks. We have, step by step, tried to establish more security in the team. To play with the quality of players we have.
"We are not quite where we'd like to be. We'd like to have an array of games where you've imposed the way you like to play. We've tried to do that step by step.
"But to give even more security, you need a number of games won where you've controlled and been dominant."