Japan's Kashima Antlers banished their continental phobia by humbling Shanghai SIPG 3-1 to take the edge in their League last 16 tie on Wednesday.
In South Korea, meanwhile, Ulsan Hyundai squeezed past K-League rivals Suwon Bluewings 1-0 at home thanks to a second-half winner from substitute Kim In-sung.
Yuma Suzuki pounced for Kashima from point-blank range just before halftime and Daigo Nishi added a carbon copy moments after the restart before a freak own goal from Shanghai defender Yu Hai on 75 minutes put the home side in total control.
Brazilian forward Elkeson snatched an important away goal almost immediately afterwards to give the big-spending Chinese club a glimmer of hope going into next week's return leg.
But Kashima -- Japan's most successful team with eight J-League titles to their name -- will fancy their chances after only their second-ever win in eight matches in the competition's knockout stage.
Shanghai, whose defeat by Urawa Reds in last year's semi-finals prompted Portuguese coach Andre Villas-Boas to step down, will rue missed opportunities after flying out of the blocks.
Former Chelsea forward Oscar wasted Shanghai's best early chance, the Brazilian acrobatically denied by Kashima's South Korean goalkeeper Kwoun Sun-tae after eight minutes with the goal at his mercy.
Elkeson then headed over before Suzuki scrambled home after Shanghai failed to deal with a corner.
More calamitous set-piece defending then offered Nishi the chance to prod home before Yu stooped to connect with a diving header that whistled past his goalkeeper Yan Junling.
Elkeson calmly side-footed home moments later, however, to give Shanghai a lifeline.
Super-sub Kim settled a dour game in Ulsan between two former Asian champions, ghosting in at the back post to score after 67 minutes with his first touch of the game.
Urawa's triumph in last year's final ended a miserable run for Japanese clubs, who had struggled to make an impact in Asia's premier club competition since the Reds lifted the trophy in 2007 and Gamba Osaka won it a year later.
Shanghai's Chinese Super League rivals Guangzhou Evergrande won the tournament in 2013 and 2015.