Hassan Al-Haydos was the head coach of Al-Duhail for ten years, from 2011 to 2021. Under his leadership, the club achieved significant success, including winning the Gulf Pro League and the AFC Champions League.

Al-Haydos' impact on Al-Duhail during his tenure was immense. He brought in a new style of play that emphasized attacking football and fast breakaways. This approach led to several exciting matches and high-scoring games, with Al-Duhail finishing as runners-up in the league four times and winning the title twice.

One of Al-Haydos' most notable achievements was leading Al-Duhail to the AFC Champions League final in 2017. The match against Al Ahly was one of the most memorable in recent memory, with both teams playing some incredible football and ending in a 2-2 draw after extra time. Al-Haydos' team ultimately lost the penalty shootout, but they left the stadium knowing they had given themselves the best chance of reaching the Champions League final since their inception in 2014.

During his time at Al-Duhail, Al-Haydos also made a number of signings that helped to strengthen the squad. He signed players such as Youssef Zayat, who went on to become one of the club's all-time greats, and Ahmed Al-Mahroushi, who is now a regular player for the Saudi national team.

Overall, Hassan Al-Haydos' impact on Al-Duhail during his tenure was profound. He transformed the club into a force to be reckoned with in the region and beyond, and he will always be remembered as one of the greatest coaches in the history of the club.