Frank Lampard has admitted that multiple Chelsea players were not fully motivated during the second half of last season.
Club legend Lampard, who is Chelsea's all-time leading goalscorer, returned to Stamford Bridge for a second stint as first-team manager in April when he was appointed on an interim basis until the end of the season.
He took charge of 11 matches in all competitions, winning only one and losing eight.
Chelsea had signed more than 20 new players over the previous two transfer windows, including 13 who featured in last season's first team.
Lampard believes that the size of the squad made the team difficult to manage.
He was not impressed by the level of commitment shown by some of his players.
Speaking this week on The Diary of a CEO podcast, Lampard said: "I could see in training the the level wasn't enough. It wasn't enough to get a result against Brentford at home or whatever, let alone Real Madrid.
"When I got there I could see the team spirit and the togetherness was not there. It was nothing bad, but you have to train elite to be elite."
Lampard's second and fourth games as Chelsea interim boss were against Real Madrid in a two-legged Champions League quarter-final.
Chelsea lost both matches 2-0, leaving them with nothing but Premier League points to play for.
With a mid-table finish looking pretty much guaranteed, Lampard was unable to get his team playing with the intensity desired.
He added: "The minute we didn't get through against Real, you're in to that end of season zone and what are you playing for? That is not the norm at Chelsea.
"At Chelsea, we should be playing for something. We played for not so much, another reason why motivation came down."
He also said: "When I came in, I noticed very quickly that some players were thinking the season was going to peter out and what the future would look like for them.
"If I'm a player that's not been playing for seven months and think I might be leaving in four weeks' time, it's probably going to be a struggle to motivate that player. I haven't got a magic wand to motivate them.
"When you have international players in a big number, you're telling internationals they have to stay at home. It's not easy."
Lampard refused to criticize Chelsea chairman Todd Boehly for his role in the club's chaotic campaign.
Discussing co-owners Boehly and Behdad Eghbali, Lampard said: "Their intentions are certainly good. I know that. I had a good relationship with them.
"Their intentions to do a good job are amazing, they want to take the club and be the best. They have great intentions.
"They've spent the money because they want to do well. If they're going to address the situation that is their strategy going forward, but I do think you will see players like Enzo Fernandez, Mykhailo Mudryk and Noni Madueke develop and they're going to be big players for the club."
Despite the poor results achieved, Lampard said of his latest spell at Stamford Bridge: "I don't have a regret about doing it.
"If people want to criticize or have a view over my six or seven weeks' work, I've got no problem with that.
"It wasn't my most favorite experience in my career but it was an experience and I have learnt from it."
Ten former first-team players have left Stamford Bridge since the end of last season.
Meanwhile, former Tottenham boss Mauricio Pochettino has been appointed as Chelsea's new manager.
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