Dutch boss Koeman backs struggling Depay to shine at Euros
Depay has come under fire after failing to score in the Netherlands' first two games of the tournament.
Following his lacklustre performance in the 0-0 draw with France, there were calls for Wout Weghorst to start against Austria.
Weghorst came off the bench to score the winner in the Netherlands' opening game against Poland.
But Koeman vowed to keep faith with a player he believes is an essential part of the Netherlands' bid to win the Euros for the first time since 1988.
"Memphis has a lot of value to the team. He is playing very well. This team utterly needs him. They have to give the ball to him," Koeman told reporters on Monday.
"Of course he will be in the initial line-up. Memphis is able to play.
"He has had a lot of injuries to face. Of course he has to play better, that is clear for all of us."
The volatile Depay, who left Atletico Madrid at the end of last season, has not helped his cause with a series of inflammatory gestures.
The former Barcelona attacker infuriated his doubters by wearing a headband with the slogan 'who cares' written on it during the win over Poland.
The 30-year-old also released a song before the tournament called "Thanks for your opinion" in a thinly-veiled response to his critics.
Despite those outbursts, Koeman is adamant ex-Manchester United forward Depay is a positive presence in the Dutch squad.
"I have good vibes because he is a very good player. He criticises himself according to how he performs," he said.
"You want to help and support the players. Memphis does not have a lack of confidence. He is sure he can find the net."
The Netherlands have finished first in their groups at each of the past two major tournaments.
After beating Poland and drawing with France, Koeman's team have their sights set on securing top spot in Group D against Austria in Berlin on Tuesday.
They will finish in first place if they better France's result against Poland.
"Of course we want to be number one in our group. That is what we want to achieve. We have to play fast and pass well because we have got to win," Koeman said.
Austria will likely go through with a point as one of the best third-placed teams but could also finish first with a win, if France fail to beat Poland.
Touted as one of the dark horses for the tournament, Ralf Rangnick's men impressed in a 3-1 victory over Poland last time out.
"Austria are playing well, we should not undervalue them," Koeman said.
"They are very intensive and do not allow the opponent to build up the play. We have to be razor sharp.
"We should not lose the ball because they will slaughter us. We have to keep it and be strong to avoid the Austrian pressure."