Bale is expected to start Sunday's visit of Burnley as Spurs aim to end a run of five defeats from six League games which has left them nine points adrift of fourth place.
The Wales forward scored in both legs of the Europa League win over Wolfsberger and impressed as a half-time substitute in last weekend's defeat to West Ham.
Jose Mourinho has favoured Steven Bergwijn, Erik Lamela and Lucas Moura this season, with Bale and Dele making just three League starts between them, but there is a sense that their resurgence could spark Spurs's flagging season into life.
Dier said: "Dele put in a fantastic performance on Wednesday and I thought he was really good in the first leg as well.
"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.
"He can pop up when you least expect it – I've always said that is one of his greatest qualities. And 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 too.
"But 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."
Spurs must improve defensively against Burnley following a string of defensive errors which have contributed to their slump since mid-December.
Dier has been particularly guilty of individual mistakes and Mourinho claimed the centre-half was suffering from a "confidence crisis" earlier this month – a suggestion refuted by Dier, who nonetheless admitted his form has dipped.
"Confidence-wise, I don’t feel like I’ve been in a bad place all season," he said. "I’ve gone through periods where I’ve had low confidence in the past so I know what it feels like and I haven’t felt that this season. The most important thing is the reality, and people’s perception versus reality can be different sometimes.
"We’ve gone through a difficult moment, but it’s important to keep things in context. I feel like I’ve been happy with my level for the majority of the season. There’s been obviously a dip in it, which correlates with the dip with the team in general and our performances in general. I don’t think my confidence has ever been in a negative place where it’s been in previous times. That’s all."
Dier has made more League appearances than any other centre-half under Mourinho but he was twice dropped following mistakes in defeats to Liverpool and Chelsea.
"I’m a big boy, this is a ruthless profession and I focus on trying to do the best that I can every time I get an opportunity," he said. "Sometimes it goes well, sometimes it goes badly but my effort never changes."
Spurs, who could welcome back Serge Aurier on Sunday, will discover their Europa League last-16 opponents on Friday afternoon in an unseeded open draw.