The pair, who will clash at the Emirates Stadium, were inseparable in the first leg at Stamford Bridge as they held one another to a 0-0 draw. They also drew 2-2 on the Gunners' home turf when they met in the Premier League on January 3.
Read on for a closer look at the contest, but first here are the viewing details you need to catch the action:
Date: Wednesday, January 24
Time: 8 p.m. GMT/3 p.m. ET
TV: Sky Sports (UK), ESPN3 USA
After remaining goalless in the first leg, a score draw in this fixture would hand Chelsea the advantage thanks to the away goals rule, though in the Carabao Cup, it only applies after extra time has been played.
Both sides warmed up for the match with impressive wins on Saturday, when Chelsea put four past Brighton & Hove Albion and Arsenal did the same against Crystal Palace.
The Gunners were 4-0 up after just 22 minutes against the Eagles, earning praise from James Olley of the London Evening Standard:
Palace eventually pulled one back in the second half, but it was nevertheless an excellent performance from Arsenal and an important one without star forward Alexis Sanchez, per ESPN FC's Mattias Karen:
The showing will serve as a confidence boost ahead of the Chelsea clash and demonstrates what the team are still capable of without the Chile international.
The Blues should prove to be much sterner opponents than the Eagles were, though, and their win at the Amex Stadium was only the third time Brighton have been beaten there in the Premier League this season.
Most impressive of all for Chelsea was Eden Hazard, who played a key role in the victory. Vaishali Bhardwaj of the London Evening Standard singled him out after the match:
If the Belgium international is in similarly excellent form on Wednesday, he'll be extremely difficult to contain.
The Gunners will need to make full use of home advantage or their cup run will come to a disappointing end.