The centre-half was given his bow at Preston North End on Tuesday.
And it was an interesting baptism to say the least as the 19-year-old began as Jonathan Grounds centre-half partner, then was the middle man in the defence after a half-time switch to a 3-5-2 formation.
"In general I would say it was a positive performance from him," commented Zola.
"In the first-half he was suffering a bit. He was a little bit exposed. But second-half he was good, so overall a positive."
Zola opted to bring Paul Robinson out of the starting line-up at Deepdale after taking into account the opposition.
"They had big bodies up front and he was given his chance as he has the size and presence to deal with those crosses into the box and those long balls Preston play.
"Also, Krystian has been impressive in training for us and showed his qualities - he deserved an opportunity."
Bielik's late, late addition on January transfer window deadline day - his loan was completed at 10.45pm, 15 minutes before the cut-off point - has proven to be a shrewd piece of business.
Michael Morrison has had to have surgery on his groins and Ryan Shotton remains sidelined, also with a groin issue.
As another January capture Dan Scarr is currently recovering from a thigh injury, Bielik has certainly bolstered those centre-half options.
And, as seen in midweek, the rising Polish star has the adaptability to play in a back three (plus he began his career at Legia Warsaw as a central midfielder).
The way the formation worked, by and large, was heartening to Zola.
Josh Dacres-Cogley came on at the break to go to the right side centre-half position; Grounds was the left side centre-half. Emilio Nsue and Cheick Keita were the wing-backs.
"We had more balance about us and it helped us control the second-half," said Zola, whose mood, though, was darkened by the way Blues conceded what turned out to the winning goal, despite their dominance.
"We have to remember to do the basics, defend with focus and be strong," he said. "You cannot afford to lose your man in the box."