Looking to make a first final appearance since its title win in 2011, host Al Sadd started brightly at Jassim bin Hamad Stadium and dominated the majority of the game but spurned a number of chances to break the deadlock.
Those missed opportunities came back to haunt the Qatari side when the Iranian champion clinched a late win with an 86th-minute penalty from Ali Alipour after the forward had been upended by goalkeeper Saad Al Sheeb.
"We controlled the match right up to the penalty,” said Ismaeil. "We felt some of their players were exhausted and so we tried to push forward to get the win but unfortunately, we ended up losing. We now look forward to going to Tehran and getting a good result there."
"We are used to seeing Iranian sides play an open game against us but Persepolis were playing in a defensive manner.”
The 2011 champion is now left with the task of becoming the first side to defeat Branko Ivankovic’s side at Azadi Stadium in the current campaign when the second leg takes place in three weeks’ time.
“I think they may play a more open game in front of their fans in the second leg and that could turn out to be good for us; we could use that to our advantage and score the goals that we are looking for,” added Ismaeil.
"Of course, we did not play as well as we wanted in this game but we now have a huge desire to perform at a higher level in Tehran and come back with a win.
“We have a good period of preparation lying ahead of us and, hopefully, Al Sadd will be in a better situation by then. What is important is that we fully believe in our chances," Ismaeil concluded.