Reigning domestic champions Guangzhou Evergrande and Esteghlal boosted their hopes of reaching the semi-finals of the AFC Champions League after posting wins in Wednesday's quarter-final first legs, while the ties involving Kashiwa Reysol and Al Shabab as well as Al Ahli and FC Seoul remain finely balanced ahead of next month's return fixtures.

Chinese champions and current runaway leaders Guangzhou left it late to record a 2-0 home win over Qatar's Lekhwiya thanks to goals from South American duo Dario Conca and Elkeson, while Khosro Heydari's fortunate second minute strike saw Iranian counterparts Esteghlal edge out Thailand's Buriram United by a single goal in Tehran.

Japanese Emperors' Cup holders Kashiwa, though, failed to make full use of home advantage as Saudi Arabia's Al Shabab fought back to claim a 1-1 draw, while Korean champions FC Seoul left Saudi Arabia with the same result after 2012 finalists Al Ahli netted a late equaliser to keep themselves in contention ahead of the second legs on September 18.

"It was a good match from our point of view even though we had a lot of chances and couldn't take more of them," said Guangzhou coach Marcello Lippi.

"I am happy but there is 180 minutes in this match so our goal is to go to Qatar and win.

"There is still a month wait until the second game so we will wait until then to think about what we will do."

In Guangzhou, a quickfire double from Conca and Elkeson inside the final 20 minutes saw Lippi's side move into a commanding position against Lekhwiya.

Conca coolly converted his fourth goal of the campaign from the penalty spot with 18 minutes remaining before Elkeson marked his AFC Champions League debut with a composed finish three minutes later to hand 2012 quarter-finalists Guangzhou the advantage.

"Marcello's side showed why they are the best in China so they are big favourites to go through, but I think we will see another Lekhwiya in a few weeks," said Lekhwiya coach Eric Gerets.

"We have nothing to lose and we will look to attack and try to create pressure from the first second and try and score a goal in the first half to make sure we have a chance in second half. It will be tough, but we will try our best."

In Tehran, Heydari's fortuitous early strike handed Iran champions Esteghlal a slender advantage over Thai FA Cup winners Buriram.

Heydari's mishit cross after just two minutes delighted a near-capacity crowd at the cavernous Azadi Stadium as two-time Asian Club Championship winners Esteghlal enjoyed the perfect start to their first-ever appearance in the quarter-finals of the AFC Champions League.

Buriram, though, were unlucky not to salvage a draw as goalkeeper Mehdi Rahmati denied Jesus Berrocal and Osmar Barba in the second half.

"We wanted to devise more attacks but we failed to do that due to poor play-making," said Esteghlal coach Amir Ghalenoei.

"We weren't stressed out, but I have to confess we weren't good enough in the second period."

Elsewhere, substitute Sultan Al Sawadi fired home from close range with 10 minutes remaining to earn Al Ahli a draw with FC Seoul at King Abdulaziz Sport City as last year's finalists maintained their unbeaten record in the competition this season.

Dejan Damjanovic's fine strike after 10 minutes had put FC Seoul, who have twice been eliminated in the quarter-finals by Middle Eastern opponents in the last five years, ahead only for Al Sawadi to finally find a response for Al Ahli after the hosts had dominated possession without reward.

"We will have a better performance in the second leg as we will hopefully put more pressure against them," said Al Ahli coach Vitor Pereira, who was taking charge of Al Ahli in a competitive game for the first time.

"We are satisfied with the performance of the players who did a great job and managed to make a good comeback."

Finally in Kashiwa, a spectacular volley from Brazilian midfielder Fernando Menegazzo earned Al Shabab a 1-1 draw with Emperor's Cup holders Reysol.

Japan international Masato Kudo had given Kashiwa, who advanced to the last eight for the first time with an unbeaten record, the lead after 21 minutes only for Menegazzo to equalise for the visitors a minute before half-time.

"We're halfway through the tie but this is a good result for us," said Al Shabab coach Michel Preud'Homme.

"I know that we have lots of things to do ahead of the second leg but I have a very positive feeling that we are becoming a good team."