Oltmans, chief coach of the Indian team, said the hosts were completely outplayed by a better Argentina team on the field today at the Sardar Vallabhbhai Patel Stadium here.
"For me the result is not important, for me what is important is performance and today our performance was by far below-par the level that we normally can show. The performance was really insufficient today," Oltmans minced no words while criticising his players.
"From my point of view we didn't stick to our game. Argentina is a team who likes to defend and rely on fast counter attacks. They didn't allow us to come to their circle too often apart from the fourth quarter. Argentina was clearly the better side today," he added.
The Dutchman, who is also the High Performance Director of India hockey, termed his side's performance as "disappointing".
"I think the players know they can play better than what they showed today. When you play the first match of the tournament you want to play your best hockey," Oltmans said.
"We went back and back and failed to go forward. In the second half we tried to go forward. In the second half we created more but still it was not enough to win against Argentina. It was a disappointing game from our point of view. But the good part is in this format we can afford that," he said analysing India's performance.
"I am not too concerned about penalty corners I am more concerned about our all over performance," Oltmans said.
India will play Olympic champions Germany tomorrow in their second match of Pool B tomorrow. "In 24 hours we play Germany, another tough match. Germany is a very strong and we have a very tough pool."
India captain Sardar Singh was of the view that there was no co-ordination between the players.
