Anderson Lopes put Marinos in front after seven minutes and Yan Matheus doubled the visitors’ advantage in the 69th minute as Harry Kewell’s side looked set to take a comfortable cushion into the return next Wednesday.

But Shandong deservedly pulled one back when Chen slammed home his 91st-minute strike after Choi Kang-hee’s side had seen Matheus Pato hit the post early in the second half.

Lopes pounced to give the former J League champions the lead, the striker capitalising on the inability of the Shandong defence to clear to slot his shot past Wang Dalei into the bottom corner.

Pato and Li Yuanyi threatened for Shandong before Valeri Qazaishivili forced a fine save from William Popp, the Yokohama goalkeeper diving to the right to keep out the Georgian’s goal-bound strike.

Just before the interval, Lopes should have doubled Yokohama’s lead but he sent Asahi Uenaka’s cross high over the bar.

Pato hit the post from close range eight minutes into the second half as Shandong pushed to level, but Marinos doubled their advantage 21 minutes from time when Yan Matheus calmly placed the ball into the net from the edge of the area.

Shandong’s desperation grew as the final whistle approached and Chen hit an acrobatic right-foot effort beyond Popp a minute into stoppage-time to keep the tie in the balance.

The winners will face Jeonbuk Motors or Ulsan Hyundai in the semis, with the first leg between the South Korean teams ending in a 1-1 draw yesterday.

On the western side of the draw, Al Ain of the United Arab Emirates hold a 1-0 lead over Al-Nassr from Saudi Arabia while Al-Hilal defeated fellow Saudis Al-Ittihad 2-0 in the first leg yesterday.