Former Chelsea defender Graeme Le Saux feels that Jose Mourinho has brought the "feel good factor" back to the club.
Mourinho returned to the club he left in 2007 back in June, and former England international Le Saux thinks that the Portuguese has given everyone concerned with the Blues a lift ahead of the new Premier League season.
"Jose Mourinho has brought the feel good factor back and it will be through the roof in the first match against Hull City," Le Saux told Sky Sports News.
"Chelsea's home form will be key [to launching a title challenge]. They need to get momentum early on. I think [Mourinho's team] will be built on that defensive foundation and he will have learned a huge amount from his time with other teams.
"He's worked with some of the best players in the world and he will have to decide how to get the most out of player such as Oscar, Juan Mata and Eden Hazard as well deciding how players like Frank Lampard can play."
The new Premier League season begins this weekend.