The match is technically Atletico's home leg despite the fact that it is not taking place in Spain, with the reverse fixture due to take place in London in the middle of March.
Atletico remain in charge of the La Liga title race, sitting three points clear of second-placed Real Madrid at the summit with a game in hand, but Diego Simeone's side will enter this match off the back of a shock 2-0 home defeat to Levante, and they have actually only won one of their last four matches.
The Madrid giants were not at their best in the group stages of this season's Champions League, winning just two of their six Group A fixtures, but a total of nine points was enough to see them advance to this stage.
Atletico overcame Liverpool at this stage of the 2019-20 competition but surprisingly lost 2-1 to RB Leipzig in the quarter-finals; the Red and Whites have actually reached the last eight or better in five of their last seven Champions League campaigns and will be confident of overcoming Chelsea.
The La Liga club have reached two Champions League and three Europa League finals in the last 11 seasons, meanwhile, and have been victorious in nine of their 11 two-legged knockout contests with English teams.
Tuesday's contest in Romania will be the first time that they have locked horns with Chelsea since the group stages of the 2017-18 Champions League, with the English club winning 2-1 in Madrid before the points were shared in a 1-1 draw at Stamford Bridge.
Chelsea, meanwhile, comfortably progressed to the last-16 stage of the tournament, finishing top of Group E having picked up 14 points from their six games against Sevilla, Krasnodar and Rennes.
The Blues also progressed to the round of 16 last season but were comfortably beaten 7-1 by eventual winners Bayern Munich, while they have only actually won five of their last 11 matches in this competition.
The London giants have played 11 two-legged knockout ties with Spanish opposition and recorded just four victories, while they have won just two of their last 11 away knockout fixtures against La Liga clubs in UEFA competition, but the fact that this game is not taking place in Madrid should help them.
Chelsea will enter Tuesday's match off the back of a 1-1 draw with Southampton in the Premier League on Saturday afternoon, which made it seven games unbeaten under their new head coach.
Thomas Tuchel led Paris Saint-Germain to last season's Champions League final, ultimately losing to Bayern, and the 47-year-old will be desperate to continue his positive start at the helm.
Atletico Madrid Champions League form: LWDDDW
Atletico Madrid form (all competitions): WWDWDL
Chelsea Champions League form: DWWWWD
Chelsea form (all competitions): WWWWWD
Atletico will be without the services of key defender Jose Gimenez, who limped off the field against Levante in La Liga on Saturday having suffered a recurrence of a muscular problem.
As for Chelsea, Thiago Silva again missed out against Southampton on Saturday due to a muscular problem, and Tuchel has confirmed that the veteran centre-back will not be available for this game either.
Atletico Madrid possible starting lineup:
Oblak; Savic, Felipe, Hermoso; Llorente, Kondogbia, Koke, Saul, Lodi; Felix, Suarez
Chelsea possible starting lineup:
Mendy; Azpilicueta, Christensen, Rudiger; James, Kante, Jorginho, Alonso; Mount, Abraham, Werner
We say: Atletico Madrid 2-1 Chelsea
Atletico will be desperate to secure a first-leg advantage ahead of a trip to London next month, and we can see the La Liga leaders edging a tight game. Chelsea are yet to ignite in the final third of the field since the change of manager, and we are finding it difficult to back the Premier League side to triumph, but a 2-1 defeat, securing a vital away goal in the process, would leave the contest delicately poised.