| Personal information | |||
|---|---|---|---|
| Full name | Mathias Flaga Olesen | ||
| Date of birth | 21 March 2001 | ||
| Place of birth | Copenhagen, Denmark | ||
| Height | 1.88 m (6 ft 2 in) | ||
| Position | Midfielder | ||
| Team information | |||
Current team | Sønderjyske | ||
| Number | 10 | ||
| Youth career | |||
| 2017–2019 | Eintracht Trier | ||
| 2019–2020 | 1. FC Köln | ||
| Senior career* | |||
| Years | Team | Apps | (Gls) |
| 2018–2019 | Eintracht Trier | 1 | (0) |
| 2019–2023 | 1. FC Köln II | 55 | (4) |
| 2022–2025 | 1. FC Köln | 41 | (0) |
| 2024 | → Yverdon (loan) | 17 | (0) |
| 2025–2026 | Greuther Fürth | 12 | (0) |
| 2026 | → Grazer AK (loan) | 15 | (1) |
| 2026– | Sønderjyske | 0 | (0) |
| International career‡ | |||
| 2017 | Luxembourg U16 | 6 | (0) |
| 2017 | Luxembourg U17 | 8 | (1) |
| 2018 | Luxembourg U18 | 2 | (1) |
| 2018–2019 | Luxembourg U19 | 8 | (1) |
| 2018–2021 | Luxembourg U21 | 11 | (1) |
| 2021– | Luxembourg | 43 | (2) |
|
* Club domestic league appearances and goals as of 6 June 2026 ‡ National team caps and goals as of 6 October 2026 | |||
Mathias Flaga Olesen (born 21 March 2001) is a professional footballer who plays for Danish Superliga club Sønderjyske. Born in Denmark, he represents the Luxembourg national team.
On 10 June 2025, Olesen signed a two-year contract with Greuther Fürth in 2. Bundesliga.
On 2 February 2026, Olesen moved on loan to Grazer AK in Austria, with an option to buy.
On 12 July 2026, Olesen signed a three-season contract with Sønderjyske in Denmark.
Olesen made his international debut for Luxembourg on 11 November 2021.
Born in Denmark, Olesen moved to Luxembourg in 2007 with his family, as his father got a job there in the investment industry. Olesen attended the European School of Luxembourg II (ESL2).
| No | Date | Venue | Opponent | Score | Result | Competition |
|---|---|---|---|---|---|---|
| 1. | 16 November 2023 | Stade de Luxembourg, Luxembourg City, Luxembourg |  Bosnia and Herzegovina | 1–0 | 4–1 | UEFA Euro 2024 qualifying |
| 2. | 26 March 2026 | National Stadium, Ta' Qali, Malta |  Malta | 2–0 | 2–0 | 2024–25 UEFA Nations League promotion/relegation play-offs |
1.FC Koln
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