Radja Nainggolan

In August 2019, Nainggolan returned to Cagliari on a season-long loan. He was named the league's MVP for November, with two long-range goals and three assists in three matches to help his team reach fourth place.

On 10 July 2019, Lai confirmed in an Instagram post that she had been diagnosed with cancer and would begin chemotherapy treatment.

On 26 June 2018, Nainggolan signed with Inter Milan for €38 million (€24 million plus Davide Santon and Nicolò Zaniolo, valued at €14 million) until June 2022. He scored in his league debut on 1 September, helping the visitors defeat Bologna 3–0, and just over a month later he netted the equaliser in a 2–1 comeback win at PSV Eindhoven in the Champions League group stage to become the first-ever Belgian to score for the club in the competition.

On 21 May 2018, after once again not being picked for the upcoming World Cup in Russia, Nainggolan retired from the international scene.

Nainggolan smoked cigarettes during his playing career. On New Year's Eve 2018, he became the subject of strong controversy in Italy after he posted a video on Instagram cursing, drinking alcohol and smoking.

On 26 August 2017, aged 29, Nainggolan announced that he would be retiring from international football after not being selected for Belgium's upcoming World Cup qualifiers, and stated that he would be focusing on his club career with Roma. However, he was selected by new manager Roberto Martínez for friendlies against Mexico and Japan in November, only to pull out due to injury.

A Belgium international for eight years, Nainggolan played 30 times for his country (scoring six goals) and represented it at Euro 2016.

Nainggolan was an undisputed starter for the Marc Wilmots-led Red Devils during the UEFA Euro 2016 qualifying campaign, scoring in an away draw with Bosnia and Herzegovina and a 4–1 win in Andorra as the team qualified for the tournament for the first time in 16 years.

Nainggolan signed a permanent deal with Roma in the 2015 off-season, for €9 million. On 6 July of the following year he renewed his contract until June 2020, extending it a further year the following summer.

On 22 February 2014, Nainggolan scored his first goal for the capital side, grabbing the 1–0 winner against Bologna. His second, which arrived on 19 April against Fiorentina (same result) ensured his team automatic qualification to the UEFA Champions League.

On 13 May 2014, Nainggolan was selected in a standby list for the 2014 FIFA World Cup. He did not make the final cut, however.

In early October 2013, after three seasons as an undisputed first-choice, Nainggolan agreed to an extension until 2016. His performances with the Rossoblu made him especially popular among their fans, who named him in a top 11 list comprising the best players in the history of the Sardinian club.

On 7 January of the following year, Nainggolan was loaned to fellow league team Roma until the end of the campaign for a fee of €3 million, with an option to purchase 50% of his rights in the ensuing summer for €6 million. He made his debut two days later, starting in a 1–0 home win over Sampdoria for the Coppa Italia which qualified to the quarter-finals. In the same competition, he also helped dispose of Juventus in said stage by playing the full 90 minutes 12 days later.

Nainggolan was selected to the finals in France. He made his debut in the tournament on 13 June, playing 62 minutes in a 0–2 loss against Italy. After featuring as a second-half substitute in the second game, a 3–0 defeat of the Republic of Ireland, he returned to the starting XI against Sweden, scoring the game's only goal at the Stade de Nice after a counter-attack to send his country to the knockout stage as second; in the quarter-finals, he netted from 25 metres to put his country ahead against Wales after 12 minutes, but in an eventual 1–3 loss.

Due to his pace, stamina, tenacity and aggressive tackling, as well as his willingness and ability to chase down and press opponents off the ball, Nainggolan is also a good ball-winner, and has frequently been used in a box-to-box role; he is also capable of playing as a winger. After his move to Roma, he was mainly deployed as a central or defensive midfielder in a 4–3–3 formation or in the "mezzala" role, and on occasion even as a right-back; following the arrival of Luciano Spalletti, however, he returned to playing in a more advanced role as an attacking midfielder or second striker in a 4–2–3–1 or a 3–4–2–1 formation. He has also been used in a more central, attacking role, on occasion, or even as a false attacking midfielder.

Nainggolan married Claudia Lai, with the couple being parents to daughters Aysha (b. 2012) and Mailey (b. 2016). His twin sister, Riana, is also a footballer.

Nainggolan's mother died in 2010, and after her death he tattooed two large wings on his back with her dates of birth and death. He was raised Roman Catholic and spoke Dutch, English, French and Italian fluently.

On 27 January 2010, Nainggolan was loaned to Cagliari with a buyout clause. He made his Serie A debut on 7 February, playing seven minutes in a 0–3 away loss against Inter Milan. After making seven appearances (including being sent off a few minutes after entering the field on 28 February against Chievo Verona), the club announced it had acquired 50% of his rights in a co-ownership deal.

In the first part of 2010–11, under manager Pierpaolo Bisoli, Nainggolan started often due to the absence of Daniele Conti. On 31 October 2010 he scored his first goal in the Italian top level, from a right-footed volley in a 2–0 home win over Bologna. On 31 January 2011, Cagliari redeemed the second half of his contract from Piacenza.

Nainggolan earned his first senior cap on 29 May 2009, against Chile in the Kirin Cup. He scored his first goal for the Red Devils on 5 March 2014, in a 2–2 friendly draw with Côte d'Ivoire.

In the 2008–09 campaign, Nainggolan became a starter for the Emilia-Romagna side, playing 38 of 42 games and scoring three goals, which contributed to them avoiding relegation.

Due to his father's heritage, Nainggolan was eligible to represent both Indonesia and Belgium, but ultimately chose to play for the latter nation. He took part at the 2007–09 International Challenge Trophy finals, a tournament which the under-23 team won.

Nainggolan began playing football with Tubantia Borgerhout at the age of 5. Seven years later he moved to the youth team of Germinal Beerschot, where he remained until 2005, when he was noted by Alessandro Beltrami and moved to Italian Serie B club Piacenza. He made his senior debut on 28 May 2006, during a home defeat to Arezzo, being inserted permanently into the first team the following season.

Radja Nainggolan (born 4 May 1988) is a Belgian professional footballer who captains and plays as a midfielder for Italian club Cagliari on loan from Inter Milan.