Mauricio Pochettino says critics may call him "crazy" but he is certain Chelsea will be successful under his management given time and patience.
Last weekend's defeat at Everton was another setback in a tough start this season for both Pochettino and his players which has seen them slide to 12th in the league.
Pochettino during the week suggested he will need yet more new signings in January, despite boasting one of the most expensively assembled squads in the world, after Reece James became the latest new name on the Blues treatment table.
The manager, who revealed at his Friday press conference that he had lost his voice from shouting at his players, said: "We knew it was going to be difficult and it is more difficult because of the unexpected circumstances that you always plan to have but not a lot.
"How we are suffering after five or six months. That is a challenge, and it is a very good thing for us, even if I am so upset and feel bad because, for sure, we want to be in a different position.
"That is the challenge and we are going to be back and we are going to fight. That type of situation will make five different options and elements, make it more clever and evolve the coaching staff.
"The challenge is massive but I really believe that we can succeed. It is a matter of time, but time is sometimes there; it's about being patient and believing in the way we are doing things.
"Of course, the most difficult thing in football is to keep believing when you don't get the result you want.
"We will succeed for sure. You will see. Maybe today you can say this guy is crazy but I am not crazy. I know what I am doing, 51 years old."
As James rejoins the crocked list, summer signing Christopher Nkunku has finally taken his name off it after four months out with a knee injury and is expected to make his debut at home to Sheffield United tomorrow.
However, first-choice goalkeeper Robert Sanchez will see a specialist over his own knee injury and Marc Cucurella also will remain sidelined.
Pochettino said: "It is very sad because we are going to lose this player for a few weeks. We still need to wait to see the situation with Reece [James] and Marc Cucurella. With Reece, I prefer not to talk.
"We will go into the situation in depth. Reece was excited about being back, and we brought him back perfectly, step-by-step playing for 25 minutes, 40 minutes, and 60 minutes. It was a perfect way to build his confidence and fitness.
"He is upset and frustrated, so we need to be careful about how we talk to find the best solution for him.
"We are here to support him to try and help, and we are all thinking in terms of finding a solution for as soon as possible to get him with the group, full recovery, then try so the same thing doesn't happen again."
Adding about Nkunku's return: "Yes, can be involved. That is very good news.
"To be involved tomorrow, be in the squad, and start to feel the competition and his team-mates after the pre-season is good news for us. We need to be calm and quiet because it is going to put all the pressure on him."
Romeo Lavia, Wesley Fofana, Ben Chilwell, Carney Ugochukwu, Trevoh Chalobah and Lesley Ugochukwu all remain out but Malo Gusto is fit again.
