Oltmans believes if things go according to plans, the team will stand a good chance to win a medal in the Champions Trophy.
"Everybody knows we are good in the knockout stage. But Champions Trophy this year will be slightly different and we need to finish top two to play the final and be top four to play for bronze.
"It will be interesting to see how our players will cope to this situation and face the challenge. Our realistic expectation is to finish in the top three," he said about his expectations from the event.
"It (Defence) is the key to a team's success at a tournament. There are times when you can't score too many goals to win a match but you can certainly win by avoiding the opponents to score," he said.
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"The Germans are known for their defence while the Australians defence is slightly unconventional compared to others and Argentina too heavily depend on their defence for good results. It helped them win bronze at the World Cup. In our structure, the entire team needs to work on defence. Some of our attackers are good in defence too and that is our strong point," the Dutchman added.
"There will be a little bit of pressure. It is a challenge the players need to be prepared for and show their best hockey. Only 16 out of 29 members in the camp will get to play at the Olympics and that is quite a sizeable number to drop," Oltmans said.
"They will have to challenge other players in the team which is why every match, every performance is important," he said.