Benfica head coach Rui Vitoria remains confident his team can seal Champions League qualification against Astana despite the absence of two key players.

Brazilian defender Luisao fractured his elbow in the Portuguese side's 2-1 extra-time loss against Sporting CP in the Taca de Portugal on Saturday and later required surgery, forcing him to miss Wednesday's crucial match.

Benfica currently sit top of Group C, two points clear of Atletico Madrid and five clear of third-placed Galatasaray and Vitoria is confident his players can guarantee their qualification with a win at Astana.

Speaking in Kazakhstan ahead of the game, he told reporters: "The team and the fans put in great performances at home against Galatasaray and Atletico Madrid. 

"Despite having injured players, I have faith in my team. 

"There are good teams in our group but Astana are one of them. We respect our opponents but we came here to win."

Benfica will also have to make do without Nicolas Gaitan, their leading goalscorer in the competition, after the attacker picked up a late second booking in their win against Galatasaray in the previous matchday.

But midfielder Pizzi shares his coach's belief in the squad's ability to cope without being at full strength.

"Luisao and Nicolas Gaitan are really important players for us," he said.

"It would be great if they were available, but we have 20 players here and we all will try to produce a good performance without them."