Kalinic has struck against Everton and Manchester City this season to equal his goal tally for the whole of last term.
Both goals have been gifts from goalkeepers Tim Howard and Joe Hart, but Allardyce told Rovers' website: "You've got to be there to finish them off, haven't you?
"Put him in front of goal and he is cool and calm. It was a little more difficult, this one, than the one he scored against Everton.
"That was a well-taken goal but this one was a lot further out, he had to make sure he got it past the last defender and just stroked it in.
"Under that pressure when everybody expects you to score, you've got to hold your nerve and make sure you do, and Niko did. That will boost his confidence very well."