Mbappe, who is Real Madrid's top scorer this season, returned to full fitness after a knee sprain that had limited his involvement in the previous round against Manchester City. Despite missing both legs of that tie from the start, Madrid progressed comfortably, but Arbeloa suggested the French forward would now take centre stage.
"I'm delighted to have that kind of problem," Arbeloa said. "To have outstanding players and someone like Kylian Mbappe, who came here for matches like this and knockout ties like this one.
"I'm sure we'll see him at his best, leading the team the way he always has. I have great confidence in all my players."
Mbappe is expected to start alongside Vinicius Junior at the Santiago Bernabeu, with Jude Bellingham also pushing to return after injury. Arbeloa admitted that selecting from such a talented squad was a challenge, but one he welcomed.
"Having Mbappe is an extraordinary piece of luck," he added. "I don't think there's a coach in the world who wouldn't want him. When you also consider players like Vinicius, Bellingham and Valverde, you understand the level we have."
Vinicius backed his teammate and dismissed any doubts about their partnership, insisting their connection continues to grow.
"People talk a lot, but 'Kyli' is here to help us," Vinicius said. "He gives us confidence, he scores goals, and we need to stay connected as a team.
"It's a difficult match where the best players make the difference, and he is one of them. I have an incredible connection with him, on and off the pitch."
Madrid head into the clash after a disappointing 2-1 defeat to Mallorca in La Liga, a result that left them trailing Barcelona by seven points. Vinicius admitted the performance fell short but expects a strong response.
"There are days when we are more or less connected, and that happened against Mallorca," he explained. "If we are not at 200 percent, we won't win games.
"I hope we are at that level tomorrow because it's a very important match for us."
The Brazilian also addressed recent incidents of discrimination in football, supporting calls for players to speak out and push for change across the game.
"If we continue this fight together, I believe future players won't have to go through these situations," he said.
