Perfect season

A perfect season is a sports season including any requisite playoff portion, in which a team remains undefeated and untied. The feat is extremely rare at the professional level of any team sport, and has occurred more commonly at the collegiate level in the United States. A perfect regular season (known by other names outside the United States) is a season excluding any playoffs, where a team remains undefeated and untied; it is less rare than a complete perfect season but still exceptional.

A perfect season may be part of a multi-season winning streak.

Exhibition games are generally not counted toward standings, for or against. For example, the 1972 Miami Dolphins (below) lost three of their preseason ("exhibition" games in 1972 NFL vernacular) games but still are considered to have had a perfect season.

American football

National Football League

Since the National Football League began in 1920, only one team has played a complete perfect season (both regular season and playoffs): the 1972 Miami Dolphins, who won their fourteen regular season games and three postseason games, including Super Bowl VII, to finish the season 17–0–0.

Real Madrid C.F.

Real Madrid Club de Fútbol (Spanish pronunciation: [reˈal maˈðɾið ˈkluβ ðe ˈfuðβol]; Royal Madrid Football Club), commonly known as Real Madrid, or simply as Real, is a professional football club based in Madrid, Spain.

Founded in 1902 as Madrid Football Club, the team has traditionally worn a white home kit since inception. The word Real is Spanish for Royal and was bestowed to the club by King Alfonso XIII in 1920 together with the royal crown in the emblem. The team has played its home matches in the 81,044-capacity Santiago Bernabéu Stadium in downtown Madrid since 1947. Unlike most European sporting entities, Real Madrid's members (socios) have owned and operated the club throughout its history.

The club is the most valuable sports team in the world, worth €2.5 billion ($3.4 billion) and the world's highest-earning football club for 2013–14, with an annual revenue of €549.5 million. The club is one of the most widely supported teams in the world. Real Madrid is one of three founding members of the Primera División that have never been relegated from the top division, along with Athletic Bilbao and Barcelona. The club holds many long-standing rivalries, most notably El Clásico with Barcelona and the El Derbi madrileño with Atlético Madrid.