Nicolas Kiefer (born 5 July 1977 in Holzminden, Lower Saxony), is a former German professional tennis player. He won a silver medal in men's doubles with partner Rainer Schüttler at the 2004 Summer Olympics in Athens.

Kiefer was taken notice of as an outstanding junior. He won the Junior Australian Open, US Open and was a finalist and semi-finalist at Wimbledon and the French Open finishing as the number 2 junior behind Mariano Zabaleta when he was 18.

On 10 January 2000, he reached his second quarter-final at the Australian Open and afterwards was ranked World No. 4, his highest position to date.

Nicolas has been known to have a few tennis superstitions. He is sometimes seen tapping his racquet on the corners of the court after a point, although the reasons behind this are not clear. He also, when serving, frequently asks for the ball with which he has just won a point to re-use it in the next one.

Kiefer became infamous for an incident on 25 January 2006, during the quarter-finals of the Australian Open. While facing Sébastien Grosjean late in the fifth set of a marathon match, Kiefer threw his racquet mid-point. Grosjean lost the point, hitting the ball into the net. Grosjean protested that the racquet distracted his shot. The umpire Carlos Bernardes said he did not believe the act was intentional and noted Grosjean had already hit the ball before the flying racquet could have had any effect on his shot. Grosjean eventually lost the fifth and final set to Kiefer. Kiefer went through to the semi-finals where he was defeated by the 2004 champion Roger Federer.

Roger Federer (German pronunciation: [ˈfeːdəʁɐ]) (born 8 August 1981) is a Swiss professional tennis player who held the ATP No. 1 position for a record 237 consecutive weeks from 2 February 2004 to 18 August 2008. Federer has occupied the #1 ranking for 285 overall weeks, one week short of the record 286 weeks held by Pete Sampras. As of 28 May 2012, he is ranked World No. 3. Federer has won a men's record 16 Grand Slam singles titles. He is one of seven male players to capture the career Grand Slam and one of three (with Andre Agassi and Rafael Nadal) to do so on three different surfaces (clay, grass, and hard courts). He is the only male player in tennis history to have reached the title match of each Grand Slam tournament at least five times and also the final at each of the nine ATP Masters 1000 Tournaments. Many sports analysts, tennis critics, and former and current players consider Federer to be the greatest tennis player of all time.

Federer has appeared in an unprecedented 23 career Grand Slam tournament finals, including a men's record ten in a row, and appeared in 18 of 19 finals from the 2005 Wimbledon Championships through the 2010 Australian Open, the lone exception being the 2008 Australian Open. He holds the record of reaching the semifinals or better of 23 consecutive Grand Slam tournaments over five and a half years, from the 2004 Wimbledon Championships through the 2010 Australian Open. At the 2012 Australian Open, he reached a record 31st consecutive Grand Slam quarterfinal. During the course of his run at the 2012 French Open in Roland Garros, Federer eclipsed Jimmy Connors long standing record of 233 match wins in Grand Slam tournaments when he defeated Adrian Ungur in a second round match.

Marat Mikhailovich Safin (Russian: Марат Михайлович Сафин, Tatar: Марат Мөбин улы Сафин, Marat Möbin uğlı Safin) (born January 27, 1980) is a Russian politician and retired tennis player of Tatar descent. Safin won two grand slams and reached the World No. 1 ranking during his career. He was also famous for his emotional outbursts and sometimes fiery temper on court. Safin also holds the record for most broken racquets in a year with 87. Safin is the older brother of former World No. 1 WTA player Dinara Safina (Dinara Mikhailovna Safina) (Russian: Динара Михайловна Сафина), born April 27, 1986 in Moscow. They are the first brother-sister tandem in tennis history to both achieve No. 1 rankings.

Safin began his professional career in 1997, and held the No. 1 world ranking for a total of 9 weeks between November 2000 and April 2001. He won his first Grand Slam title at the 2000 U.S. Open after defeating Pete Sampras, and won the 2005 Australian Open, defeating Australian Lleyton Hewitt in the final. Safin helped lead Russia to Davis Cup victories in 2002 and 2006. Despite his dislike of grass courts, he became the first Russian man to reach the semi-finals of Wimbledon at the 2008 Wimbledon Championships. At the time of his final Grand Slam appearance at the US Open on September 2, 2009, Safin was No. 58 in the official world men's tennis rankings.

Peter "Pete" Sampras (/ˈsæmprəs/; born August 12, 1971) is a retired Greek–American tennis player and former world number 1. During his 15-year tour career, he won 14 Grand Slam singles titles and became recognized as one of the greatest tennis players of all time.

Sampras debuted on the professional tour in 1988 and played his last top-level tournament in 2002 when he won the US Open, defeating rival Andre Agassi in the final. He was the year-end world no. 1 for six consecutive years (1993–1998), a record for the open era. His seven Wimbledon singles championships are also an Open Era record. He spent 286 weeks at no. 1, the most of any male player. His five US Open singles titles is an Open Era record shared with former world no. 1 players Jimmy Connors and Roger Federer. Sampras is the last American male to win Wimbledon (2000) and the ATP World Tour Finals (1999).

Eckart von Hirschhausen (born August 25, 1967 in Frankfurt am Main, Germany) is a German physician and comedian.

Eckart von Hirschhausen studied medicine, supported by a scholarship from the Studienstiftung des deutschen Volkes (Study foundation of the German people), at the Free University of Berlin, the University of Heidelberg and the University of London. The subject of his doctoral thesis was 'Efficiency of intravenous immunoglobulin therapy on pigs in the hyperdynamic phase of endotoxemia' and he graduated magna cum laude from the University of Heidelberg. From 1996-1997 he studied scientific journalism at the Free University of Berlin, but without taking a degree.

In 1996 he started writing, mainly for Focus and Der Tagesspiegel. His first appearance on television is believed to have been as a guest contestant performing magic tricks in Jürgen von der Lippe's show Geld oder Liebe ('Money or Love'). From 1998 to 2003, he hosted the weekly health advisory show Service: Gesundheit ('Service: Health') on Hessischer Rundfunk Television. Since 2004 he has been a weekly contributor to Stern: Sprechstunde ('Stern: Consultation Hour'): his column is called Die Etwas Andere Medizinkolumne ('The Somewhat Different Medicine Column').