But they showed their class at the Kingspan Stadium on Friday as they comprehensively dispatched Toulouse 38-0.
Tries from Nick Williams, Andrew Trimble, Luke Marshall, Stuart McCloskey and Chris Henry did the damage for Ulster while Pienaar was named man of the match for his efforts.
But the South African is well aware that the job is far from done in Europe and Ulster will need to match their levels next weekend.
"It was a fantastic performance by the boys," he said. "We disappointed ourselves against Saracens a few weeks ago and to put up a performance like that is fantastic for us.
"There is still a long way to go and it's taken a while to put a performance out like this, we'll enjoy it but the hard work starts again on Monday.
"Both the attack and defence made us proud, we pride ourselves on defence and the boys showed a lot of character. We'll enjoy this but we have a long way to go, we're in a tough group and we know that. This will mean nothing if we can't back it up next week.
"Any French side at home are dangerous, we know Toulouse are a fantastic side, we respect them a lot but I think it will be a different ball game next week over there."
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