Thus far he has won 87 men's doubles titles (with 9 different partners), including a Gold medal at the 2000 Summer Olympics, four ATP World Tour Finals, and eight Grand Slam men's doubles titles attained with three different partners. In addition, Nestor has won 4 Grand Slam mixed doubles titles: 2007 Australian Open with Elena Likhovtseva, the 2011 Australian Open with Katarina Srebotnik, and the 2013 Wimbledon and 2014 Australian Open with Kristina Mladenovic. His 87 men's doubles titles make him the third most decorated champion among doubles players. He was the first player in doubles tennis history to win every Grand Slam and Masters Series event, the Year End Championships and Olympic gold medal at least once in his career, an achievement that has since been matched by the Bryan Brothers. He was named ATP Doubles Team of the Year in 2002 and 2004 (with Mark Knowles) and 2008 (with Nenad Zimonjić). He became the World No. 1 ranked doubles player in the world in August 2002. Nestor's career-high singles ranking is World No. 58, which he reached in August 1999.
Nestor won three Grand Slam doubles titles together with longtime partner Mark Knowles of the Bahamas. The tandem won the 2002 Australian Open, the 2004 US Open and the 2007 French Open. He and Knowles also reached the final of the 1995 Australian Open, the 1998 French Open and US Open, the 2002 French Open and Wimbledon and the 2003 Australian Open. Nestor won three Grand Slam titles with Nenad ZimonjiÄ (2008 Wimbledon, 2009 Wimbledon and 2010 French Open) and two with Max Mirnyi (2011 French Open and 2012 French Open). He also reached two more finals with ZimonjiÄ, the 2008 French Open and 2010 Australian Open.
In mixed doubles, he reached his first final at the 2003 US Open with Lina Krasnoroutskaya. He made it to the 2006 Australian Open and 2006 French Open finals, as well as winning the mixed doubles event at the 2007 Australian Open with partner Elena Likhovtseva. He won his second mixed doubles title at the 2011 Australian Open with Katarina Srebotnik. Nestor also won the 2013 Wimbledon mixed doubles title with Kristina Mladenovic (they also reached the 2013 French Open mixed doubles final together).
At the 2000 Summer Olympics in Sydney, Australia, Nestor and partner Sébastien Lareau won a gold medal, the first and only medal so far in tennis for Canada. The duo won four more titles together during their career. After the Olympics, Nestor won one title with Kevin
Ullyett in November 2000 and two with Sandon Stolle in 2001.
He has been a member of the Canadian Davis Cup team since 1992. He first came to prominence in the public eye that year by defeating then world number one Stefan Edberg in a hard-fought singles match in Vancouver. He was part of the squad who made history for Canada in 2013 as they were the first Canadian team in the Open Era to reach the World Group semifinals.
Nestor won his first doubles title in Bogotá, Colombia with Mark Knowles in 1994. They defeated French Open champions Luke and Murphy Jensen in the final.
On July 5, 2006, he participated in the second-longest match in Wimbledon history, lasting 6 hours and 9 minutes.
Daniel parted ways with long-time doubles partner Knowles after the 2007 US Open (won a total of 40 titles together), then started a partnership with Nenad Zimonjic. He won a doubles title with Zimonjic at the 2007 St. Petersburg Open. Nestor and Zimonjic advanced to the 2007 Paris Masters final as the second seeds, but lost to no. 1 doubles team Bob and Mike Bryan.
Knowles partnered Nestor once again and won the 2007 Tennis Masters Cup. It was a fitting end for one of the most successful doubles teams to ever play the game. They defeated Simon Aspelin and Julian Knowle to take their first Tennis Masters Cup title. Nestor chose to partner with ZimonjiÄ because he felt as though the game had transformed into a more power and physical version of doubles. It was reported in the New York Times that "on the tour, it's known that they (Nestor and Zimonjic) joined up, after years in the top 5 with other partners, specifically to usurp the Bryans."
In 2008, Nestor and Zimonjic won the first title of their partnership at the Hamburg Masters. They reached the final of the French Open a week later. He captured the 2008 Wimbledon title for the first time, winning over Jonas Björkman and Kevin Ullyett. Thus he managed to complete the career Golden Slam. The pair also captured the 2008 Tennis Masters Cup. In 2009, they won the Wimbledon title again and won eight more titles (most titles for Nestor in one year so far in his career).
Nestor and Zimonjic won the French Open and were runners-up at the Australian Open in 2010. In October 2010, the duo announced that they would split up at the end of the 2010 season. However, they finished their partnership on a high note by winning the ATP World Tour Finals in London. The pair won a total of 24 titles together. Nestor paired up with Max Mirnyi in 2011.
His first tournament with Max Mirnyi in Brisbane was his 783rd career doubles victory, overtaking Todd Woodbridge's total of 782 for the all-time match wins record. Nestor and Mirnyi won the 2011 French Open and the 2011 ATP World Tour Finals in London. In the final of the ATP World Tour Finals, he played his 1,148th match, an all-time record. Nestor won one more Grand Slam title with Mirnyi when they captured their second straight French Open in 2012. Nestor won a total of eight titles during his partnership with Mirnyi.
Starting in January 2013, Nestor decided to partner with Mahesh Bhupathi. He however changed to play with Robert Lindstedt later during that year. Nestor won his 81th doubles title, the Winston-Salem Open, in August with new partner Leander Paes. He also became the first player in ATP history to score 900 career doubles wins.
(taken from Wikipedia, July 2015)