On May 31, Mahious joined USM Alger for three seasons, coming from CA Batna for 3,000,000 DA.[1] He made his debut for the team in the CAF Confederation Cup during a win against Rayon Sports, later in the Arab Club Champions Cup Mahious scored the winning goal against Al-Quwa Al-Jawiya his first goal with the club.[2] On August 14, He made his debut in the Ligue 1 against DRB Tadjenanet as a substitute and made an assist for Zakaria Benchaâ in 3–1 victory.[3] On September 21, and in the first game as a starter Mahious managed to score his first goal in the Ligue 1 against AS Ain M'lila in 3–0 victory.[4] On July 1, Mahious returned to USM Alger after 6 months on loan to AS Ain M'lila, due to the financial crisis Mahious became an important player in the team On 25 August 2019, scoring his first goal in CAF Champions League against AS Sonidep in a 3–1 home win.[5] Then he led USM Alger to victory against Gor Mahia outside the home by scoring a double.[6]
Today, I bid farewell to my first home USM Alger, after 5 years I spent in this ancient team, this team that gave me everything, thanks to God, and thanks to our dear team, I joined the U-23 and Algeria A' teams and the Algeria national football team. Love and appreciation especially in the difficult times that I lived through after my injury after the final of the CHAN and in the death of my mother, thanks to the players with whom I spent unforgettable days.
— A message of thanks and farewell from Aymen Mahious on Instagram.[7]
On 5 January 2020, in the Algerian Cup Mahious scored his first hat-trick in his career and made an assist for Billel Benhammouda against USM Khenchela in 6–1 victory.[8] Before the start of the 2020–21 season, Mahious received an official offer from Mamelodi Sundowns, but the sports director Antar Yahya refused to release the player to any team.[9] Aymen Mahious the demand has become high from several clubs, including Umm Salal of Qatar and Zamalek of Egypt, especially since his contract expires at the end of the season.[10] On June 3, 2023, Mahious won the first title in his football career by winning the 2022–23 CAF Confederation Cup after defeating Young Africans of Tanzania.[11][12]
Yverdon-Sport
On August 9, 2023, Aymen Mahious joined the newly promoted club in the Swiss Super LeagueYverdon-Sport for three seasons.[13] On 11 August 2024, Mahious joined Algerian club CR Belouizdad on loan for the season.[14]
In the final Mahious missed a decisive penalty shootout which was the reason for losing the title, Mahious was criticized for the way he takes penalties, and he apologized to the Algerian people but he said that he would continue to take penalty kicks in that way.[21] Mahious won the Golden Boot Award at the end of the tournament and was included in the squad for Best XI.[22] May 30, 2023 the FAF publish the list of Djamel Belmadi for the two matches of the month of June, Where is called Mahious for the first time and his first match was against Uganda in the Africa Cup of Nations qualification.[23]