Antonio Conte admitted that Chelsea are "in trouble" after a third Premier League defeat of the season against Crystal Palace saw them slip nine points adrift of leaders Manchester City in the title race.
Wilfried Zaha's second-half strike earned Palace their first win of the season at Selhurst Park on Saturday after Tiemoue Bakayoko had cancelled out an own goal from Cesar Azpilicueta, and Chelsea's misery was compounded by a suspected hamstring injury that forced Victor Moses off after 40 minutes.
Conte is already without midfielders N'Golo Kante and Danny Drinkwater as well as striker Alvaro Morata due to injuries, though the latter is back in training with a view to featuring against Roma on Wednesday after nursing a hamstring problem during the October international break.
Chelsea's title defence is already on the rocks after three losses in their first eight Premier League matches, and Conte is under no illusions as to the task ahead.
"I think every season is different," he told reporters. "Last season is the past. Now it is another squad, different players and for this reason, if we compare last season, we didn't play Europa League or Champions League.
"This season we are facing four competitions and we are having a few problems doing this. When you have a few injuries, you are in trouble."
Chelsea's players have usually been granted a day off after a match during Conte's time in charge, but were pictured training at Cobham on Sunday following their lacklustre performance against Palace.
"We mustn't be happy," Conte added. "This season will be very difficult for us. For this reason we have to put 150 percent in; 100 percent won't be enough. I have players with a great will to work and fight.
"For sure we have to find the strength to overcome this moment. Everyone can see our situation. You know very well the potential of the other teams but it is important for us to look at ourselves.
"This season will be difficult but also we have to understand we have to try to build something important for the future, to give the opportunity to the new players to have more experience in this league, to give the opportunity to young players to show they deserve to stay and play for Chelsea. We must have patience this season to understand it won't be easy."
Michy Batshuayi was granted his first Premier League start since the opening day of the season but failed to impress at Selhurst Park, being replaced by Pedro Rodriguez after just 57 minutes, and he reacted with frustration to being substituted.
"I didn't see this," Conte said of Batshuayi's reaction. "But it is normal to be angry after a bad performance -- but every player had a bad performance.
"I trust in every player and try to give everyone the opportunity to take the chance. But also because we have Morata and then Batshuayi [as our only strikers]. The performance of the whole team was bad. Not one or two players."