Marcos Alonso Mendoza

Bolton Wanderers Alonso joined Bolton Wanderers of the Premier League for an undisclosed fee, on 27 July 2010. He made his competitive debut for the club in a 1–0 away win against Southampton in the League Cup on 24 August. His first league appearance arrived on 1 January 2011, starting for suspended Paul Robinson in a 2–1 away loss to Liverpool at Anfield.

Alonso scored his first goal for Bolton on 31 March 2012, the second of an eventual 3–2 away victory over Wolverhampton Wanderers. At the end of the 2012–13 season, he was voted The Bolton News player of the year, winning 37% of the vote: Marc Iles wrote, "...this has been a break-out season for the former Real Madrid starlet. Alonso has grown in stature and become a consistent performer at full-back – chipping in with some important goals too."

Fiorentina

In May 2013, Alonso signed for Italian side Fiorentina on a three-year deal, despite being offered a new contract by Bolton manager Dougie Freedman. As he was under the age of 23 when leaving, the former were forced to pay the latter £400,000 in compensation. He played his first match on 7 January 2014, featuring the full 90 minutes in a 2–1 home win over Manchester United in the League Cup semi-final first leg and being given the Player of the match award by Sky Sports. He took part in the final of the competition on 2 March, not being able to prevent a 3–1 loss against Manchester City; he contributed 20 appearances in all competitions, helping his team to retain their top-flight status.

Upon his return from loan, Alonso became a regular, making over 70 appearances in his final two seasons in purple. On 19 March 2015, he scored his first goal for the Viola, in a 3–0 defeat of fellow Italians Roma in the round of 16 of the UEFA Europa League.

Chelsea

On 30 August 2016, after 85 games with Fiorentina, Alonso completed his move back to England after signing a five-year contract with Chelsea worth around £24 million. He made his debut on 20 September, featuring 120 minutes in the 4–2 win at Leicester City in the League Cup third round, and four days later he first appeared in the league in a 3–0 away defeat to Arsenal, coming off the bench for Cesc Fàbregas in the 55th minute.

Alonso scored his first goal for the club on 5 November 2016, in a 5–0 victory over Everton at Stamford Bridge. He added two more at the King Power Stadium, in a 3–0 win against Leicester on 14 January 2017; he eventually totalled six goals for the league champions.

In April 2018, Alonso came under extensive criticism for seemingly purposely digging the studs of his boots into Shane Long's leg during a tackle in a league game against Southampton. He was not reprimanded in any way by referee Mike Dean – who came under similar criticism – but was later charged with violent conduct by The Football Association, and later issued a three-match ban. He scored a career-best seven league goals during the campaign, eight in all competitions, adding his only FA Cup by beating Manchester United 1–0. On 8 May, he netted the winner as his team defeated Manchester City 2–1 at the Etihad Stadium. He was an unused substitute in the final of the UEFA Champions League in Porto against the same opposition (1–0 victory), but started and finished both legs of the round of 16 tie against Atlético Madrid. He captained the club for the first time on 11 September 2021, in a league fixture at home to Aston Villa.

Barcelona On 2 September 2022, Alonso agreed to a one-year contract at Barcelona after leaving Chelsea by mutual consent a day earlier. He scored his only Champions League goal on 1 November, opening the 4–2 away win over Viktoria Plzeň in the group stage.

In March 2023, Alonso's former sides Unión Adarve and Bolton Wanderers questioned the legality of the transfer and lodged complaints to FIFA over it; they alleged that they were due compensation, stating entitlement as he was on their books before the age of 23. scoring his only goal on New Year's Eve in the 1–1 home draw with Espanyol in the Derbi Barceloní.

Celta Alonso signed an initial one-year deal with Celta de Vigo on 28 August 2024, as a free agent. He finished his debut campaign with four goals, three in the league for the seventh-placed side.

International career On 16 March 2018, Alonso received his first call-up for the Spain national team for friendlies against Germany and Argentina later that month. He debuted against the latter on the 27th in a 6–1 win at the Wanda Metropolitano where he replaced Jordi Alba with 11 minutes left, making the Alonsos the first Spanish family to have three generations of internationals and seventh worldwide.

Personal life Alonso's grandfather, Marcos Alonso Imaz (better known as Marquitos), played with Real Madrid's first team for eight years. His father, Marcos Alonso Peña, spent several seasons in Spain's top flight, most notably with Atlético Madrid and Barcelona, and both represented Spain at senior level.

Drunk driving incident On 3 May 2011, Alonso was the driver in an accident causing the death of a young woman in Madrid. He was the driver of a car that collided with a wall, killing one of the passengers, a 22-year-old woman, having been driving at in wet conditions in a zone, with a blood alcohol content of 0.93 mg/mL of blood. He faced 21 months in prison when sentenced in February 2016, but his punishment was changed to a €61,000 fine and a driving ban of three years and four months, which had already been spent.

Career statistics Club

International

Honours Sunderland Football League Cup runner-up: 2013–14 FA Cup: 2017–18; runner-up: 2016–17, 2019–20, 2020–21, 2021–22 UEFA Champions League: 2020–21 UEFA Europa League: 2018–19 UEFA Super Cup: 2021 FIFA Club World Cup: 2021 EFL Cup runner-up: 2018–19, 2021–22

Barcelona La Liga: 2022–23 Supercopa de España: 2023

Spain UEFA Nations League runner-up: 2020–21

Individual PFA Team of the Year: 2017–18 Premier League