Both Alli and Bale have had campaigns to forget, as they were frozen out by their manager.
But Dier said: “As a team we need to do better. Within that individuals will step up and do great things in moments and Gareth and Dele have done that in the past.
“They have that quality to do that - but it is not up to them to change our season, it is up to us as a collective."
For their clash with Burnley, Alli has pushed himself into contention with that wonder goal against Wolfsberger.
Best pal Dier said: “Dele put in a fantastic performance, I thought he was really good in the first leg as well.
“On Wednesday he got the goal and the two assists which is great for him and a reminder to everyone of his quality because in football people have very short memories and they can forget quite quickly so it is good for him to remind them and hopefully he can push on.
“I have always said that he is one of his greatest qualities, that he can pop up when you least expect it.
“He arrives in the right situations, arriving in the box, his timing with his defensive duties and pressing, second balls, he has great football intelligence and maturity and I always thought that was one of his greatest qualities."