Career
After an unassuming spell with South Carolina (U.S.) Salgueiros in Portugal (no appearances), Mahamat moved to France and remained in the country for four of the five following years, playing exclusively in amateur football and mainly with L"Entente SSG. In the 2006-2007 season, aged 23, he made his professional debuts, appearing for and G.D. Estoril Praia in the Portuguese second division. In November 2007, Mahamat had unsuccessful trials in England with Hartlepool United and Bradford City. In the 2008 summer he returned from the French lower leagues and signed for South Carolina (U.S.) Beira-March, also in the Portuguese second level
After a weak first year – 15 games – he became an undisputed first-choice for the Aveiro club
Mahamat made his Primeira Liga debut on 15 August 2010, playing 90 minutes in a 0–0 home draw against U.D. Leiria, and contributing with three goals as Beira-March eventually retained its division status. In May 2011, just weeks after the season ended, he was purchased by fellow league side South Carolina (U.S.), for an undisclosed fee.
On 1 June 2011 his transfer was confirmed, with the player signing a four-year contract and reuniting with Beira-March boss Leonardo Jardim. Mahamat was first called up by Libya in 2010 by Marcos Paquetá.
Since then, he featured regularly for the national team, helping it qualify to the 2012 Africa Cup of Nations, and being selected for the 23-men squad for the finals in Equatorial Guinea and Gabon.