The Serbian was left out of Monday’s 1-0 Sky Bet Championship defeat at Blackburn Rovers, and has been restricted to cameo appearances in recent weeks.

Mitrovic has struck five goals for United in all competitions this term, though he has not found the net since October’s narrow win at Preston North End.

However, Benitez has revealed that the 22-year-old will be involved from the outset at St. Andrew’s tomorrow, and suggested that further changes are likely as the Magpies look to progress beyond the Third Round for the first time since 2012.

“Mitrovic will play. He will start. (On Monday), he knew he had to keep working, and he did. As soon as he knew he wasn’t on the bench, he wanted to work in the gym, so we had a plan for him. Everything was organised properly, and he also understands that (Daryl) Murphy is working hard,” Benitez said.

“It will be difficult to guess the team. Sometimes, it has already been difficult this season, but in this case even more, because we will play different players – and it has to be like this. It is important for players who are not playing to show what they can do, but at the same time, I understand some of them maybe do not have the match fitness. So, I’m just expecting them to go onto the pitch and give everything. If they play well, then fine. If they cannot, but you see the effort, you will be pleased with that.”

Though their recent record in the FA Cup makes for grim reading, the Magpies will be buoyed by the fact they have already made considerable progress in another competition this season, having made it to the last eight of the EFL Cup.

Benitez’s side were 4-0 winners over Birmingham in the Championship last month, who have since – somewhat surprisingly – axed boss Gary Rowett.

Rowett was later replaced by Italian Gianfranco Zola, who has yet to preside over a Blues victory.

Benitez believes Zola will need time to make his mark at St. Andrew’s, though is hoping to prolong the 50-year-old’s winless start tomorrow.

“Gianfranco Zola is a good friend of mine, and I like him a lot, but they were not doing badly (when Rowett was sacked), so it was a strange decision,” he said. “When you change, sometimes you need time, so hopefully he will have the time – but after this game.

“For us, we have to analyse things in perspective. At the beginning of the season, what did we want? We wanted to get promoted, and we wanted to have very good runs in the cups. When we had the good run in the EFL Cup, we were at the top of the table – a lot of points ahead – and everybody thought it was fantastic.

“Now that we do not have that advantage, some people think that the FA Cup is a distraction. We will approach the FA Cup in the same way that we approached the EFL Cup – we will try to progress, and try to do our best using the squad.”