Eleven places in the next phase of the UEFA Cup are at stake -- and some of the tournament's biggest names could miss out.
Roma, Monaco, Hamburg, Sampdoria, Palermo and Bolton are among the clubs playing today and tomorrow which have yet to qualify for the round of 32.
Defending champion CSKA Moscow, which has finished its matches, will need results go its way in Group B to advance in European soccer's second-tier competition.
Thirteen clubs have already qualified. For Friday's draw, they'll be joined by the eight clubs that finished third in their Champions League groups: Club Brugge, Thun, Udinese, Lille, Schalke, Rosenborg, Real Betis and Artmedia Bratislava.
CSKA Moscow dropped down from the Champions League last year on its way to winning Russia's first European club title and is the only previous champion left in the field.
CSKA needs Marseille to beat Dinamo Bucharest by two goals or more while Levski Sofia gets at least a draw with Heerenveen. Marseille and Levski are already through to the next round.
Roma needs a home win over Basel in Group E on Thursday to advance. If Roma loses, Red Star Belgrade, European champion in 1991, will qualify if it draws with already-qualified Strasbourg.
Roma is coming off a 2-1 home Serie A loss on Sunday to Palermo. Fans booed the team off the Stadio Olimpico pitch after the defeat dropped the club to 10th in the standings.
Captain Francesco Totti is a questionable starter due to a foot bruise, while striker Vincenzo Montella and Brazilian Amantino Mancini are sidelined with injuries.
Coach Luciano Spalletti and the players refused to speak with the media pending a tense meeting with club owners.
Palermo is also hoping to advance, needing only a draw against Brondby in Group B today. The Sicilian team is coming off its first win in six league matches.
"We played well, with great concentration in Rome," coach Luigi Del Neri said.
In the other Group B match, Espanyol needs a draw against last-place Maccabi Petach-Tikva. The Spanish side will be without coach Miguel Angel Lotina, who starts a four-game touchline ban for his red card in the UEFA Cup game with Brondby on Nov. 30.
Espanyol's assistant coach, Bartolome Marquez, is also suspended by Spanish authorities for another breach of rules.
Hertha Berlin needs a draw against already-qualified Steaua Bucharest to advance from Group C. Lens has to beat Sampdoria to qualify. A point will be enough for Lens if Hertha loses.
Group A is the only of the eight where no team has yet advanced. Monaco plays bottom side CSKA Sofia and needs a point to go through. Hamburg will qualify if it avoids defeat against Slavia Prague. The Czech side needs a win.