The Stamford Bridge outfit have had an autumn blip, with a 2-1 defeat at home to Liverpool on Sunday making it three league defeats on the bounce for the London side.
The Blues face a tricky trip to the BayArena in midweek in the Champions League, but despite a drop in form the Portuguese coach is keeping upbeat.
“We have to believe in the work we are doing to get back to winning ways,” he told The Guardian.
“The players have immense talent and I have faith in them, and you can’t forget we are still in all four competitions. But now we have to focus just on what we are doing.
“The Premier League has got more difficult but it’s not impossible [still to win it]. We have to trust the December fixtures and, above all, we have to find the belief again to fight for the title.
“But the most important thing is finding winning ways straightaway, if possible, against Leverkusen which is a massive game.
“Then we have three games in the Premier League where we must try to get nine points. The challenge is to have the belief and strength to fight for those nine points. But if we get nine points, it would put us in a different perspective,” he concluded.
Chelsea are now 12 points behind runaway leaders Manchester City and sit in fifth place currently.
By Gareth McKnight