Career
He represented the Netherlands national team at Euro 2012 and therefore is the youngest player ever at a Union of European Football Associations European Championship. Sparta Rotterdam
Willems began his career with Spartaan "20, and moved to Sparta Rotterdam. In Sparta he progressed through the club"s youth categories, and made his debut on 16 January 2011, in a match against Go Ahead Eagles.
He made 16 appearances in the Dutch second division.
PSV
On 31 August 2011, Willems joined PSV Eindhoven, on a three-year contract. He received the Number. 43 jersey.
He made his PSV debut on 23 October, in a match against Vitesse Arnhem. Willems became the youngest Dutchman to play in a Union of European Football Associations competition when he started against Hapoel Tel-Aviv, on 3 November.
In the same month, he was permanently promoted for the first team squad.
In December, Willems was targeted for a move to Manchester United, with Sir Alex Ferguson looking for "the next Patrice Evra". On 3 April 2012, his contract was broken and extended until 2016. Willems scored his first professional – and PSV – goal on 22 April 2012, against Nippon Electric Corporation Nijmegen.
With this goal, he became the youngest goalscorer in the 2011-2012 Eredivisie.
He experienced a great amount of playing time in the 2011-2012 season because Erik Pieters was injured. Although being young and quite inexperienced, he quickly showed evidence of his raw talent, especially his technique and attacking traits.
On 15 July 2015, Willems had a serious injury and missed the first half of the 2015-2016 season. While being selected for the Under-19 squad, on 7 May 2012, Willems was named in the provisional list of 36 players for the Euro 2012 tournament, one of nine uncapped players to be chosen by Netherlands manager Bert van Marwijk as part of the preliminary squad.
He was still in the Oranje Euro 2012 squad, after Van Marwijk had made a first cut to 27 players on 15 May 2012.
Willems also made the final cut into the 23-man squad, being given the number 15 shirt. He made his first unofficial appearance for the senior national team on 22 May 2012 in a friendly match against Football Club Bayern Munich. On 26 May 2012, Willems made his first appearance with Netherlands, in a match against Bulgaria.
At the European Championships, Willems made his first start for the Netherlands, against Denmark, becoming the youngest ever player to play at the Euros and the fourth-youngest player to play for the Netherlands, at 18 years and 71 days of age.
The record was previously held by Belgian Enzo Scifo, at 18 years and 115 days. He featured in all the group stage games.
However, the Netherlands were eliminated from the tournament after losing all three group games.