Oltmans spoke after the home team finished its first practice session ahead of the tournament beginning on Friday.
The hosts go into the tournament after losing the test series against Australia.
"We are taking one match at a time. The India-Australia series is over and now it's the past. We have moved on from there and now all our efforts are focused on giving a good performance at the World League Final. The good news is that all our players are fit and there is no injury in the team, which just gives us a lot of confidence ahead of our first encounter," said Oltmans.
Thimmaiah made it 5-0 after he got a short forward pass inside the circle from Surender Kumar in the 34th minute before China earned the two successive penalty corners.
Goalkeeper Chikte did well to palm away a rising drag-flick from Chinese penalty corner shooter Cheng Xi Yuan in the 36th minute.
A minute later, Upadhyay shot on target for India's sixth goal after receiving a square ball from Affan inside the scoring circle that beat the Chinese goalkeeper. Upadhyay had all the time to control the ball and then flick it into an open goal.
Akashdeep then scored his second goal in the 39th minute as he picked the ball on the left flank and moved square to shoot home from the top of the circle.
In a quick turnaround, Sardar Singh sent a cross from left on which Affan capitalised for his second goal.
Jasjit rounded off the Indian scoring in the 51st minute with his second strike in a goalmouth scrimmage that saw the defenders ward off two Indian tries before Jasjit's shot sounded the boards.