LONDON (THE GUARDIAN) - Antonio Conte has warned that Chelsea will find it difficult to retain the title after their shock defeat by Crystal Palace and questioned whether his squad is strong enough to compete on several fronts.

In an echo of his frustration in the summer about the club's failure to acquire a number of key transfer targets in preparation for their involvement in the Champions League, Chelsea's manager bemoaned his team's lack of depth after an insipid performance away to the Premier League's bottom side.

The champions lost 2-1 at Selhurst Park on Saturday (Oct 14), slipping nine points behind Manchester City at the top.

Although the Italian refused to criticise his players for a lack of effort against Palace, he suggested Chelsea may have to downgrade their sights for the season and warned that a mounting injury list has left them vulnerable before they host Roma in the Champions League on Wednesday.

"We mustn't be happy," he said. "This season will be very difficult for us. For this reason we have to put 150 per cent in; 100 per cent 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.

"I think every season is different. 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 travelled to Selhurst Park without Danny Drinkwater, N'Golo Kante and Alvaro Morata.

They fell to their third defeat in eight top-flight matches.