David Moyes's team face Chelsea, Manchester City, Liverpool, West Bromwich Albion and Swansea City in their first five games of the Premier League campaign.
Vidic told the club's official website: "We always use that game [at Wembley] as a real test before the season starts.
"Of course, we want to win the trophy but when you look at the fixtures we've been given [at the start of the season] I think it's the toughest games we've been given for the last seven or eight years.
"We know we need to be ready and prepared and that's why it's been really good to see how focused the players are since we got back."
Vidic and his teammates are in competitive action for the first time next week when take on Wigan Athletic in the Community Shield.