Torres has not scored in the Premier League for three months and has netted just twice in his last 11 matches in all competitions. Ba, who missed a number of chances in the 2-0 win against West Ham before the international break, has struck just once in his last 10.
Interim manager Rafa Benitez said: "The only thing you can do with them [the strikers] is keep practising and then they will have the confidence to score the goals. They are practising, they are both working hard and doing extra work.
"They do specific work at the end of training, sometimes they will stay and work on movements and finishing.
"It is what you have to do, to keep on doing different movements, to have a different approach. We analyse the movement and will say 'okay, go here', but they know what to do so it is a question of luck, maybe.
"Fernando was training really well, scoring a lot of goals in training sessions and he then scored [in the 3-1 win against Steaua Bucharest].
"Demba Ba is a great finisher and is a great finisher in training sessions. Against West Ham he was unlucky in some situations, the keeper was doing well, but it's not normal. You can see how they train, how they practise, that they have the ability to finish, against West Ham it was a bad day [for Ba] but he can score goals."