Centre-backs Andreas Christensen and Gary Cahill have partnered one another three times across the two cup competitions they have played in so far this season, and Sarri could use his reserve partnership to spare David Luiz and Antonio Rudiger to focus on league action.
Second tier Middlesbrough also reached the next round with a 1-0 win over Premier League Crystal Palace as manager Tony Pulis got one over his former club thanks to a thunderbolt finish from Lewis Wing. Derby will make a better go of this than many think, but in the end Chelsea's current midfield form will continue.
With Jorginho and N'Golo Kante likely to be rested, there are spots open for squad players to shine.
Who do you think Sarri should start - Kovacic, Barkley or Loftus-Cheek? It won't be a happy homecoming for Frank Lampard, despite the crowd serenading him every fifteen minutes.
Arsenal set up the north London derby in the quarterfinals by beating third-tier Blackpool 2-1 in a match both teams finished with 10 men.
Incredibly, this wasn't to be the end of Derby County's bad-luck.
GK Willy Caballero, 6 - Could do nothing about either of Derby's goals, but his distribution was poor and nothing about him inspired confidence in his defenders.
Frank Lampard tasted defeat on his first trip to an adoring Stamford Bridge as a manager, falling 3-2, but not before his vibrant Derby County side gave Chelsea a significant scare in the Carabao Cup fourth round - with returning loanees Mason Mount and Fikayo Tomori both making an impact.
Yet while Derby were obliging, they always carried a potent threat of their own with Mount and Harry Wilson pesky.
Once the niceties are out of the way and the game is underway the Rams will discover that Sarri's Chelsea are no Mourinho United.
Ross Barkley registered two assists and a goal against Burnley in his most impressive performance of the season so far, and Zola said there are elements of Barkley's game that remind him of Derby boss and Chelsea legend Frank Lampard. A goal from Olivier Giroud in the first half will supplement Loftus-Cheek's.
Gabe Henderson: 3 - 1.
Though left to rue a missed opportunity to reach the quarter-finals, Lampard was upbeat after the match and appreciative of the adoration he continues to receive four years after exiting Stamford Bridge. Although Derby will get a goal that'll spark a fight in the Championship side, the Blues will ultimately prove too much for them.