Chelsea's centre-back Gary Cahill has called the club's disappointing 2015-16 season "unacceptable," but believes it can provide a building block for next year's project.
The 2014-15 Premier League champions laboured through a disastrous defence of their title, which included the mutual parting of ways with manager Jose Mourinho in December.
Guus Hiddink's appointment saw the Stamford Bridge club's results improve, with the Dutchman helping the Blues into the knockout stage of the Champions League and a 10th-place league finish after flirting with relegation under Mourinho.
The club's crowning moment may have come in their 2-2 draw with Tottenham earlier this month -- a result that ended their London rival's Premier League title hopes and handed Leicester City an improbable title.
But despite the late surge in form, Cahill told the club's website the season simply wasn't good enough.
"The season was not good at all, it was obviously disappointing and it didn't go to plan for us," Cahill said. "But all we can do now is go again next season.
"We know it is unacceptable for a club like Chelsea to have a season like we have had this year. We take this bad taste in the mouth into next year because we don't want to have it again.
"We don't want to have a period of playing football matches for nothing. It is the worst feeling ever so we need to remember this time.
"What doesn't kill you makes you stronger and we need to be stronger for this."