Win against India was good for SAfricas morale
"I think it was really a good psychological boost for us, going ahead in this tournament. It was a very important game for us in the tournament and from a psychological point of view," the 49-year-old told reporters here.
"I think defeating India has been good for us, good for our morale."
South Africa beat India by three wickets in a last-over thriller in which they were chasing an imposing 297 in Bangalore.
But the former medium pacer said the team was in no mood relax and were aware of Ireland`s giant-killing status.
"We are fully aware of what Ireland have done and can do and so it`s important how we prepare, not just from a tactical point of view but also from a mental point of view. But we are certainly aware of that," he said.
"Absolutely, impressed (of Ireland`s performance). Not just their fielding but the way they`ve played at this tournament. They`ve impressed everyone at this tournament so we are going into tomorrow`s game we`ve got a tough opponent," he added.
With matches against minnows Ireland and Bangladesh up next, South Africa have a strong chance to top group B but van Zyl said they were not looking that far.
"When we left South African shores we said we would take it one day and one game at a time. We are just focussing on the match against Ireland at the moment."
Refusing to divulge the team, the coach said, "It all depends on availability. If there are injuries then we will have to enforce changes as you know."
South Africa opted not to train today but that did not mean they were short of practice, he pointed out.
"Because we are not training doesn`t mean we are not prepared. This is part of our preparation, having close games.
"Sometimes you just get caught up with, do you have to practice or do you practice for the sake of practicing. But being prepared is important and this is part of our preparation."
On the conditions, he said, "We are well-aware of what`s expected with day-night matches in Kolkata. But I`m yet to see what`s the pitch is going to be like."