Real Madrid have won the Champions League in three of the last four seasons. United, meanwhile, have missed out on qualification for Europe's top club competition in two of the last four campaigns.

They will return to the Champions League next season after winning the Europa League. But first they face the reigning European and Spanish champions in Skopje.

And Mata insists it is a chance to show the rest of Europe how strong a team Jose Mourinho has built.

He said: "We talk about Real Madrid and we talk about the Champions League winners, which is the best trophy you can win in European football.

"They are the ones that everyone wants to beat. They have a great team and won the league in Spain as well. We know how good they are.

"But United have a great history and a great record of titles. We want, sooner rather than later, to be where Real Madrid were last season, which is in the Champions League final. We know we are on our way and building a strong team.

"I think [the gap] is not very big. We are talking about the best teams in the world, Real Madrid, Barcelona, Bayern Munich. Manchester United is there."

Despite Mata's confidence, Mourinho suggested that the talent gap was a little wider than his player believed.

"We are going to try but the difference between the Champions League winners and Europa League winners is obvious," Mourinho said. "The Europa League is very difficult to win. There is a difference of quality but we believe it's possible.

"My team should play and enjoy this special moment. It's not many times in a player can play in the Super Cup unless you are Real or Barcelona, winning European trophies regularly."

After facing Real in Macedonia, United head back to Manchester before to starting their Premier League campaign against West Ham on Sunday.

Michael Carrick can complete a clean sweep of club trophies by lifting the Super Cup at the Philip II Arena. More importantly for the United captain, he insists it would be the ideal way to start the new season.

He said: "It's hugely important, it's a huge game. I don't think you can underestimate what we've gone through to get to this stage, to play in this game. It's a big achievement.

"We are taking it very seriously. It's a big trophy to win and to kick-start the season like that would be terrific for us. It's not one that I've managed to win and I don't think anyone has in our squad so we're all desperate to do that.

"It's one I haven't won yet but it's not about me, it's about the team and hopefully we can be successful."

In the build-up to the game, Mata announced he is set to pledge one percent of his salary to charity in the hope more his fellow professionals do the same. The Spaniard revealed he has already received plenty of support.

"Football is a great sport that we all love, but it means much more than that for a lot of people around the world," he added. "I am trying to bring football together as a tool for social change. Together we can be stronger and make a real impact in the world.

"There has been a great reception, not just from players but almost everyone around the football world. I had some personal messages on my phone and messages through social media. I am quite happy with the reception.

"I think everyone understands the situation and I feel that everyone is looking forward to help. It's a very positive start."