FCSB, or former Steaua Bucuresti as many know them, did well to hold Sporting CP to a goalless draw in the first leg, but they still face a difficult task in the return match.
The Lions failed to create an advantage seven days ago despite dominating the encounter, and they will now be under pressure in Romania.
FCSB are slowly returning to where they belong after a difficult period and they were unfortunate to miss out on the league title due to inferior head to head record alone.
The Red and Blues have invested considerable funds into the playing squad of late, with Denis Alibec, Constantin Budescu, Romario Benzar, Dragos Nedelcu and Florinel Coman all joining the ranks.
Some of these players are unavailable for the play-off clash against Sporting CP, but they hope to be able to help in the group stages.
FCSB did well to record a 6-3 aggregate win over Viktoria Plzen in the third qualifying round, while they surprisingly kept a clean sheet in the first match with Sporting.
The hosts face some selection problems ahead of the return leg as key midfielder Mihai Pintilii is banned, while Dragos Nedelcu, Artur Jorge, Florinel Coman and Romario Benzar are not registered.
Probable starting line-up (4-2-3-1): Nita – Enache, Larie, Momcilovic, Junior Morais – Popescu, Achim – Teixeira, Budescu, Tanase – Alibec.
Sporting CP couldn’t mount a serious title challenge last season, but they eventually clinched the top 3 finish and the final Champions League berth.
The club have since recruited the likes of Jeremy Mathieu, Fabio Coentrao, Bruno Fernandes, Seydou Doumbia, Cristiano Piccini and Marcos Acuna, thus seriously reinforcing the playing squad.
Sporting in turn enjoyed a bright start to the league campaign, winning all three matches without conceding, but they failed to defeat Steaua in the first play-off leg.
The 5-0 triumph over Vitoria Guimaraes at the weekend seriously boosted the team’s morale ahead of the very important game, where they are 19/20 to emerge victorious.
There have been some good news for coach Jorge Jesus as key defender Jeremy Mathieu recovered from injury, but youngster Daniel Podence has been left out despite starting the first leg.
This means that Bruno Fernandes is certain to start, while summer recruit Stefan Ristovski is ineligible having represented HNK Rijeka and William Carvalho is also out as he nears West Ham switch.
Probable starting line-up (4-2-3-1): Patricio – Piccini, Coates, Mathieu, Coentrao – Adrien Silva, Battaglia – Gelson Martins, Bruno Fernandes, Acuna – Dost.