Sarri will aim to win his first trophy as Chelsea FC manager when his side take on Manchester City in the League Cup final on 24 February at Wembley.
After heading in goalless at the interval, Joshua King struck twice while further goals from David Brooks and Charlie Daniels sealed a memorable victory for Eddie Howe's side and condemned the Blues to their worst league defeat in 23 years.
Having recently publicly criticised his players, Sarri kept them in the dressing room for around an hour after the defeat.
On Daniels' goal, he added: "The whole crowd understood, he's had a hard time, but with the strength of character he has showed he deserved that moment with the crowd".
After the latest setback, he locked them in the changing room for almost an hour, having told the rest of the coaching staff, including Chelsea great Gianfranco Zola, to leave. We conceded the goal very early in the second half but we had 43 minutes so all we needed to do was to continue to play. Bournemouth had lost their last 10 games against the so-called "big six" in the Premier League but here they were able to impose their will while simultaneously crushing Chelsea's spirit.
"The clean sheet is something we had to improve and change, the whole team defended so well tonight and if you saw that you wouldn't think that is where we have struggled this season". It's hard to understand why.
"You can tell he's not at the top [of his shape] yet", Sarri said of Higuain to Gazzetta dello Sport. To lose 4-0 as Chelsea players is unacceptable. "We need to understand where the problem is". "Of course I'd like to see him stay and I'd also say that he has the potential to be the best player in Europe currently" added the Italian coach.
The manner of the defeat means Chelsea drop out of the top four, with London rivals Arsenal taking their place by virtue of goals scored.
'They already contacted me, but I wanted to move to England at the time.