Guus Hiddink urged Chelsea to think carefully about their immediate future after the reigning Premier League champions bid farewell to the Champions League with a 2-1 defeat at home to Paris Saint-Germain.
Zlatan Ibrahimovic volleyed a 67th-minute winner from close range to give the runaway Ligue 1 leaders a 4-2 aggregate triumph in their last-16 tie after Diego Costa, who excelled for Chelsea and cancelled out Adrien Rabiot's opener, limped off due to a hip injury.
A return to Europe's elite club competition next season is somewhat improbable and Hiddink expects his long-term successor to be tasked with an important rebuilding job.
Chelsea are still unbeaten in domestic competitions since Hiddink's December appointment, but the shambolic start to their title defence under Jose Mourinho means they lie 10th - 10 points behind fourth-place Manchester City having played a game more.
"Everyone, in my opinion, knows Chelsea is in a transition period," the veteran Dutchman told a post-match news conference.
"They must go on and make up the lost terrain of where Chelsea need to be. Chelsea must consider the short-term future and how to handle this.
"I was disappointed after the game. When you analyse the game we started too respectfully.
"You must be careful not to be outplayed in the first part of the game, but we were too respectable. They went 1-0 up and then we started to win some duels and got the equaliser.
"There were some chances both ways in the first half. In the second half we pushed and we were on the edge [of scoring] in the 65th minute, and in the 67th minute they killed the game."
Eden Hazard produced the latest nondescript performance of an often disappointing season for Chelsea and was booed by a section of the home support when he was substituted in the 77th minute.
The Belgium international swapped shirts with PSG star Angel Di Maria at half-time and Hiddink was keen to defuse any ill-feeling towards his player.
"I haven't seen [the shirt swap] but I am aware of it," he added. "It should not be done but in some countries it's usual that you do it.
"Maybe they are both used to doing that. I don't want to see a bad thought about that. It's not a big issue for me."
On the booing, he added: "[The fans] have the right to do what they want. [Hazard] was having a problem with a hip injury."