Chelsea's poor start to 2019 has coincided with reports that many players have become disillusioned and disengaged with Sarri's methods.
Premier League leaders City thrashed Chelsea at the Etihad Stadium, but Guardiola said he knows how dangerous Maurizio Sarri's side can be.
Man City face Chelsea on Sunday for the Carabao Cup (11.30 a.m. ET, ESPN+), the first big trophy of the season. Here's what you need to know.
Maurizio Sarri warned that it would be a disaster should Chelsea tart off the way they did against Malmo when they face City on Sunday.
Chelsea's 2-0 home defeat to Manchester United in the FA Cup fifth round on Monday was their fifth loss in 12 matches in all competitions in 2019.
Tottenham boss Mauricio Pochettino hit out at those who compare his club to the heavyweights of Europe.
Sarri criticised Hazard after Chelsea's 2-0 defeat to Arsenal and made a remarkable claim that some players are "extremely difficult to motivate."
"I was joking with [assistant manager] Jesus [Perez] about that. It's a little bit unlucky," Spurs boss Mauricio Pochettino said.
Mauricio Pochettino makes teams better and improves players, but after another semifinal defeat for Spurs, one big question remains: Is he a winner?
It took penalties but Chelsea overturned a first-leg deficit in their Carabao Cup semifinal, N'Golo Kante and Eden Hazard earning top marks.
The struggles of Eric Dier and Fernando Llorente saw Chelsea reverse Tottenham's first-leg lead en route to knocking Spurs out of the Carabao Cup.
Chelsea beat Tottenham on penalties in their Carabao Cup semifinal to advance to the final after the tie finished tied 2-2 on aggregate.
"[We must] protect the habit -- the habit of getting into the final," Guardiola said after Manchester City booked their spot into the Carabao Cup.
Harry Kane's decisive penalty in the 1-0 first Carabao Cup semifinal win against Chelsea was awarded by the video review system.
Man City's second leg was a glorified training session as players like Benjamin Mendy worked on fitness and youngsters like Eric Garcia impressed.
Chelsea have completed the signing of Argentina striker Gonzalo Higuain, who will join the club on loan from Juventus until the end of the season.
Mauricio Pochettino admits Tottenham have lost Dele Alli at "one of the worst moments" with the midfielder out until March.