McCall was appointed on a contract until the end of the season last month, and on loan striker Vuckic has told the official Gers website what he has improved most heavily.
The former Rangers star has had an immediate impact since his return to Ibrox, with his most impressive result coming in the Gers last game - a 2-1 victory over Championship champions Hearts.
The club have now moved above Hibs into second place with a game in hand, and although they cannot achieve automatic promotion, a play-off place is all-but guaranteed.
Vuckic has been vital in this upturn in fortune, with his five goals in nine games doing much to ease McCall’s tenure in charge.
He may be the only one of five loanees from Premier League side Newcastle to have made an impact at Ibrox, but the forward is worth all the praise he has been receiving, and it would come as no surprise to see McCall attempt to make the move a permanent one in the summer - if he is still in charge.
Not only is Vuckic impressing, but the Slovenian striker has been impressed by McCall since taking charge. Having been at the club under the previous regime, the 22-year-old has highlighted the coach’s main improvement from before he was at Ibrox.
Speaking to the official Rangers site, Vuckic said: “Since Stuart McCall came to the club I have been really happy. He knows what he is talking about and we follow his gameplan and everything he says.
“When I came here, the changing room was a little bit down because of the situation that is now in the past. It's good now as with the new staff coming there has been a new enthusiasm and motivation. Players are fighting for their chance in the team and our quality of training has improved. The most important thing though is that we are winning games.”