The winners of Benfica and Napoli will go through in first place in Group B but, with Beşiktaş only a point behind, defeat in Lisbon could result in elimination.
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The top two teams in Group B go head-to-head on the last day with first place the prize for whoever wins in Lisbon. Both SL Benfica and SSC Napoli will go through if Beşiktaş JK lose at already-eliminated FC Dynamo Kyiv on the same night, while Napoli beat Benfica on matchday two so will qualify with a draw.
• The teams both have eight points, one more than Beşiktaş, and Benfica will be hoping they are not made to pay for allowing the Turkish hosts to recover from going three goals down after 31 minutes on matchday five to force a 3-3 draw.
• On the same night Napoli also suffered frustration as they were held to a 0-0 draw at home by Dynamo.
• The matchday two fixture found Benfica on the wrong end of a scintillating attacking display as Napoli surged into a 4-0 lead by the 58th minute, with Dries Mertens twice on target. Rui Vitória's side made the scoreline respectable with two late goals.
• The line-ups in Lisbon on 2 October 2008 were:
Benfica: Quim, Luisão, Sidnei, Pereira, Yebda (Binya 77), Jorge Ribeiro, Di María (Urreta 78), Katsouranis, Amorim (Martins 72), Reyes, Gomes.
Napoli: Gianello, Maggio, Rinaudo, P Cannavaro, Contini, Blasi, Gargano, Hamšík (Russotto 67), Vitale (Mannini 78), Zalayeta, Lavezzi (Denis 72).
• José Antonio Reyes and Nuno Gomes scored second-half goals to give Benfica the 4-3 aggregate win. In Naples Christian Maggio scored the third for Reja's home team with Luisão quickly replying.
• The Eagles had one of their own players to blame for their inability to take all three points on matchday one. Talisca, loaned to Beşiktaş, earned the Turkish visitors a 1-1 draw in Lisbon.
• The Portuguese side won three of their five home games in last season's competition, losing 2-1 against Club Atlético de Madrid on matchday six. They were knocked out by FC Bayern München in the quarter-finals (0-1 away, 2-2 home).
• A 2-1 aggregate win over Juventus (winning 2-1 at home) helped the Portuguese side reach the 2013/14 UEFA Europa League final. They lost the final, which was also at the Juventus Stadium, 4-2 on penalties to Sevilla FC after a 0-0 draw.
• Benfica have played 30 games against Italian clubs with the record W9 D5 L16 (W6 D4 L2 in Lisbon). They lost the final of the 1965 European Cup against FC Internazionale Milano in Milan and have twice lost European Cup finals to AC Milan, 2-1 in London in 1963 and 1-0 in Vienna in 1990.
• Arkadiusz Milik scored two first-half headers on matchday one to help his side come from behind to beat ten-man Dynamo 2-1 in Ukraine.
• Qualification could have been sealed on matchday three – the earliest in UEFA Champions League history – but Beşiktaş ran out 3-2 winners in Naples and then threatened another victory in the return only for Marek Hamšík's stunning equaliser to make it 1-1.
• In their last UEFA Champions League appearance, in 2013/14, the Serie A runners-up won at Olympique de Marseille but lost at Arsenal FC and Borussia Dortmund and failed to get out of the group despite collecting 12 points – more than any other side who has failed to get through.
• Napoli won 1-0 at FC Porto on their first visit to Portugal, a 1974/75 UEFA Cup second round tie. They then repeated that scoreline in the return. Since that season, however, their four visits have produced two defeats and two draws.
• Napoli's 11 games against Portuguese sides have ended W5 D4 L2 (W1 D2 L2 away).
Coach and player links
• Vlad Chiricheș played in the Benfica academy between 2007 and 2009.
• Júlio César spent seven years with FC Internazionale Milano between 2005 and 2012, helping the Nerazzurri to win the UEFA Champions League in 2010. In 2011/12 Maggio and Marek Hamšík scored past César in Napoli's 3-0 win in Serie A.
• In the 2013 FIFA Confederations Cup group stage, Júlio César was beaten by Emanuele Giaccherini's goal in Brazil's 4-2 win over Italy in Salvador.
• Eliseu played for SS Lazio in 2009/10.
• Milik scored from the spot for Poland but Eliseu's Portugal prevailed 5-3 in the shootout in the UEFA EURO 2016 quarter-final at Stade Vélodrome.
• Luisão scored past Pepe Reina in Benfica's 1-0 win over Liverpool FC in the UEFA Champions League 2005/06 round of 16 first leg.
• International team-mates:
Ljubomir Fejsa, Andrija Živković & Nikola Maksimović (Serbia)
Rafael Cabral & Jonas (Brazil)
• Andreas Samaris will incur a suspension with his next booking.
• The matchday two loss to Napoli and Friday's Liga defeat by Marítimo are Benfica's only defeats in their last 29 games.
• Eliseu suffered a right thigh injury in the 3-0 success against Moreirense FC on 27 November and was subsequently ruled out for four weeks.
• Alex Grimaldo (abdominal muscle) has not played since 1 November; Jonas (out since 27 August, foot) is still sidelined.
• Napoli have won only four of their last 12 matches.
• Hamšík has scored 104 goals for Napoli in all competitions, putting him equal third with Edinson Cavani on the club's all-time list, which is led by Diego Maradona (115).
• Milik, scorer of seven goals for Napoli this season, ruptured the anterior cruciate ligament in his left knee while playing for Poland against Denmark on 8 October.
Teams taking part in all of the matchday six UEFA Champions League and UEFA Europa League matches will observe a minute's silence to pay respect to the victims of last week's air disaster involving the Chapecoense team and accompanying delegation. The Brazilian club lost most of their players and coaching staff in the accident, which occurred in Colombia, where Chapecoense were due to play the first leg of the Copa Sudamericana final against Atlético Nacional.
"European football is united in expressing its deepest sympathy to Chapecoense, the Brazilian Football Confederation [CBF], CONMEBOL and the families of all the victims," said UEFA President Aleksander Čeferin. "This tragedy has shaken the world of football, and we would like to send our support to all of those affected by it."