In total, this is the 19th season that the Premier League side have competed in the European Cup, but it is their first campaign in five years, with last season's second-place finish in the Premier League enough to secure automatic qualification.
Liverpool won the competition in 2005 after overcoming AC Milan in the final, but lost out to the same opponents two years later. They were last in the group stages in the 2009-10 season, but finished third in their group before reaching the semi-finals of the Europa League.
The Reds have faced Bulgarian opposition eight times in total, winning six times in the process, but they did lose 1-0 to CSKA Sofia at Anfield in 2005. Liverpool also enter the match off the back of a disappointing 1-0 home defeat to Aston Villa in the Premier League.
Ludogorets, meanwhile, are in the group stages of the Champions League for the first time. They beat Steaua Bucuresti on penalties in the final qualifying round to make this stage, but they did reach the last 16 of the Europa League last season in their debut appearance.
The visitors have won only seven of their 15 matches in all competitions this season, but they sit third in the Bulgarian league having taken 15 points from their first eight games.
Head coach Georgi Dermendzhiev has no fresh injury concerns, however, and is expected to name a front three of Roman Bezjak, Virgil Misidjan and Marcelinho. The former scored 20 times for the Bulgarian side last season and is seen as their biggest threat.
Possible starting lineups
Liverpool: Mignolet; Manquillo, Lovren, Sakho, Moreno; Gerrard, Henderson; Sterling, Coutinho, Lallana; Balotelli
Ludogorets: Argilashki; Moti, Aleksandrov, Minev, Junior; Abalo, Dyakov, Espinho; Marcelinho, Bezjak, Misidjan
Sports Mole says: 3-0