Daniël Johan Nico Willemsen (born 7 May 1975 in Lochem, Gelderland) is a Dutch sidecarcross rider and ten times World Champion.

[3] After finishing third in 1997, suffering a bad accident at the German GP,[2] and second in 1998, the two won their first world championship in 1999, taking it out by one point and beating the then current champions Kristers Serģis / Artis Rasmanis.

In February 2000, the two brothers had a serious accident in a training run in Italy, which saw Marcel temporarily parallised and unable to continue his career.

An injury prevented Grütter from taking part in the first race of the season and Willemsen replaced him with Bruno Kaelin for the first round.

[7] Willemsen temporarily switched to Ondrej Cermak as his passenger for the first of two German GP's because of an injury to Verbrugge.

Willemsen and his passenger clinched the World Championship at the second-last race of the season, at Slagelse, Denmark, having a 53 point lead over Latvians Jānis and Lauris Daiders at the time.

[9] The last race event of the 2011 season saw the World Champions, Willemsen and Verbrugge, failing to score any points.

Verbrugge however was injured during a fall and had to be taken to hospital where his arm was placed into a plaster, ruling the team out of the race.

Haralds Kurpnieks broke his wrist in the first Grand Prix of the season and replacement Kenny van Gaalen suffered a knee injury in the second French Grand Prix, making Lauris Daiders his passenger for the last five GP's.

[11][12][13][14] At the opening GP of the 2013 season in Fraunefeld, Switzerland, Willemsen suffered eleven fractures when his sidecar overturned and he had to be removed by paramedics.

[16] The team missed the last two grand prix of the season because of injury and finished ninth overall in the World Championship.