Benfica coach José Mourinho has not given up hope that his team can advance past the opening phase, despite four defeats in as many games.
Tuesday's 1-0 home loss to Bayer Leverkusen left Benfica second-from-bottom in the 36-team table with zero points.
"Nobody can convince me that we're out," Mourinho said after the game.
"If everyone starts shouting that we're out, they won't convince me. I can't say that we're going to qualify, but I refuse to accept that it is over now; there are 12 points to play for. We have a chance, the team is improving, there's nothing that convinces me that we can't fight."
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Mourinho, 62, took charge of the Portuguese giants in September after Bruno Lage was sacked following the team's 3-2 home loss to Qarabag in their Champions League opener.
The former Chelsea coach, who won the Champions League with FC Porto in 2004 and Inter Milan in 2010, said: "We don't need 12 points to qualify, nor 11, and I think not even 10.
"But we have [upcoming games against] Napoli, Ajax, Juventus, Real Madrid ... We have two games until the end of the calendar year, and if we get six points, we're in the race."
Benfica, who are third in the domestic league, play at Ajax on Nov. 25 before hosting Napoli on Dec. 10 in their last Champions League game of the year.