Derby boss Frank Lampard makes his first competitive return to Stamford Bridge as a manager, when he aims to cause an upset in the EFL Cup on Wednesday.
Lampard's side have been in excellent form lately, and are starting to justify exactly why they are considered to be one of the favourites for promotion this season.
The Rams are currently unbeaten in five league matches and they have earned points against their promotion rivals Middlesbrough and West Brom in recent weeks.
It was the win over the Baggies which stood out, with Lampard's side having no problem in ruthlessly sweeping Darren Moore's team away as they ran out 4-1 winners at The Hawthorns.
The form shown by the likes of Harry Wilson is certainly something to get excited about for Derby fans, who will be hoping they can continue their excellent run of form when they travel to Stamford Bridge this week.
But who do Chelsea need to be wary of ahead of their game tomorrow?
Find who poses a threat for Derby here....
Wilson has been in the form of his career in recent weeks and has fully justified his place in Frank Lampard's starting XI lately.
The on-loan Liverpool winger has shown real quality in front of goal and has made a name for himself for scoring stunning long-range goals.
Chelsea will be reluctant to give any free-kicks away with Wilson already showing he can deliver from a dead ball situation against Manchester United in the previous round of the EFL Cup.
Chelsea's decision to allow their on-loan midfielder to play in this fixture was a surprising one.
The 19-year-old will be hoping to prove himself to Chelsea in this game and they will already be wary of the threat that the youngster poses to their side.
Mount has three goals to his name this season and will be looking to continue his impressive run of form for Lampard's side.
Marriott was an outcast towards the start of the season, but has certainly taken his chance since returning to the team.
The former Peterborough United striker has netted three goals in his last four games and he will be pushing for a start after his recent good run of form.
He faces competition from the likes of David Nugent for a starting spot in Frank Lampard's squad.