Robi Hansda scored the only goal of the match in the added-time of the second half at the GMC Balayogi Athletic Stadium.
Aiming at the top left corner, Mumbai City FC goalkeeper Phurba Lachenpa produced a timely save to keep scores level.
Hyderabad played their opening home match at the Shree Shivchhatrapati Sports Complex in Pune due to the ongoing renovation on the pitch at their home ground, the GMC Balayogi Athletic Stadium in Gachibowli in Hyderabad.
Marquez had only two training sessions with the team before naming a 26-member squad featuring new and returning players as India adapts to life after Sunil Chhetri's retirement.
India had won the title in 2018 and 2023, while it was the first trophy for Syria who had finished third in 2019.
The athletics event gets underway at the Afro Asian Games on Tuesday, but the starting list of foreigners is still unknown.
According to sources, Assam was voted ahead of Assam, Goa, Haryana and Jharkhand, who had also bid to host the 2004 event.
Kerala were jolted right at the beginning when central defender Gianni Zuiverloon picked up an injury.