By FOX Sports staff
Although they were expected to be dominated by the Iranian giants at the Azadi Stadium, Buriram put in a remarkable display and dominated large parts of the encounter but were ultimately beaten by Khosro Heydari's fortuitous strike in the second minute.
But Drulic, standing in for coach Scott Cooper in the post-match press conference, believes there were plenty of positives to take from Wednesday's game.
"It wasn't a bad game," he said on the AFC's official website. "We played really well and had a much better ball possession during the whole match, but we were unlucky to concede as early as the second minute.
"Usually when you fall behind shortly after the start, players will get stressed out and caught off guard but we didn't panic and we maintained our mastery over the hosts. We also had some very good chances to level the match."
And given the way his charges more than matched their more-illustrious opponents, Drulic believes they have what it takes to overturn the deficit on September 18 when both sides meet again in the second leg at the New I-Mobile Stadium.
"We came to Tehran for a win but we lost the match and we have to return home empty-handed," he added. "But I am very optimistic for the return match and I feel we [can] make it to the next round, since we have the potential to be among the last four.
"I'm certain the fans watched a very good game this evening [Wednesday] and they all enjoyed themselves. I'm pretty much sure the Thai supporters [will] watch the same quality game when we play at home on September 18."
Drulic also believes the humid conditions in Thailand could play a huge part as Buriram look to make the most of their home advantage next month.
"I can't elaborate further on our plans for the return leg," the Serbian explained. "But I'm positive that the excessive humidity in Thailand will be troubling for Esteghlal, who are unaccustomed to such weather conditions.
"I'll also cross my fingers that our injured players can recover before the second match so we can use them in the line-up."
Buriram have enjoyed an excellent year so far and are currently second in the Thai Premier League, two points behind Muangthong United with a game in hand, and are also still in the running to win both the FA Cup and League Cup.
Image courtesy of Buriram United FC