Gary Cahill concedes Chelsea lost their way tactically under Jose Mourinho, but believes the team is making great strides under Antonio Conte to overcome last season's "disaster".
Mourinho led the Blues to a Premier League and League Cup double in the 2014-15 season, but his second spell in charge at Stamford Bridge came to an end in December last year after Chelsea lost nine of their opening 16 Premier League games and they eventually slumped to a 10th-place finish.
The Portuguese's relationship with key players came under scrutiny, while key players such as Eden Hazard suffered a dramatic dip in form.
Hazard aimed a thinly veiled dig at Mourinho when he told L'Equipe "Conte knows how to treat players having played at the highest level himself" and centre-back Cahill concedes all was not well at Stamford Bridge last term.
"We needed organisation," the England defender said. "We went from winning the league to the disaster of last season. We lost our way tactically, everyone's head was in different directions.
"Everyone had different situations going on, whether you're playing or not, the manager, or this or that. Different distractions are never healthy.
"It is the hardest thing when everyone is not on the same wavelength. People talk as if you wake up one day and suddenly you're a bog standard player. It doesn't happen."
Conte was chosen as Mourinho's full-time successor after Guus Hiddink took over on an interim basis last term, and the Italian has overseen three wins from as many Premier League matches to start the season.
And Cahill says the squad is fully behind what the former Juventus and Italy coach is trying to implement at Stamford Bridge.
"The main thing for me is how fit and sharp we look, and the organisation in terms of where players need to be," he added.
"We needed to have a game plan, the tactics and way we want to play drilled into everyone and everybody buy into it. That's what we have seen.
"We have worked very hard and we are buying into what is happening here. That's the most important thing - to move forward."