Jeju United of Korea Republic suffered a disappointing AFC Champions League debut after Yu Dabao's second-half goal clinched a 1-0 win for China's Tianjin Teda at Jeju World Cup Stadium.
Following a goalless first half, the host was caught out by an incisive Tianjin counter-attack as Zhang Xhaobin forged down the right before delivering a cross to the near post that the Jeju defence was unable to cut out and Yu hooked in.
Jeju came close to snatching a point late in the game when substitute
Gamba Osaka began its Group E campaign in emphatic fashion with a 5-1 demolition of Melbourne Victory at Expo '70 Stadium.
The host went in front when Takahiro Futagawa delivered a corner that Takuya Takei converted unmarked in the middle of the box.
Adriano added a second from the spot two minutes later and Lee Keun-ho effectively put the encounter to rest with a third in the 11th minute as he stabbed home from close range.
Melbourne pulled a goal back when Archie Thompson was brought down and Kevin Muscat converted from the spot but Gamba restored its lead just after the hour mark when Adriano fed Takahrio Futagawa, who picked his spot. Kim Seung-yong then headed home a late fifth.
Hangzhou Greentown enjoyed a successful start to ACL life with a surprising 2-0 win over Nagoya Grampus in Group F at Yellow Dragon Stadium.
Substitute Ba Li proved the architect of the debutant's opening victory, setting up Luis Ramirez to open the scoring shortly after the hour mark before wrapping up the points with a fine effort.
Group B saw Pakhtakor and Al Nassr share a 2-2 draw at Pakhtakor Stadium.
The host went in front on the stroke of half-time when Sherzod Karimov cut in from the right and beat goalkeeper Abdullah Al Anzi with a curling effort.
Bader Al Motwaa levelled from close range five minutes into the second period but Pakhtakor regained the ascendancy when Kakhi Makharadze nodded Karimov's free-kick back across goal and Dilshod Sharofetdinov headed in.
The Saudi outfit equalised for a second time, though, when Mohammad Al Salhawi's cross was turned into his own net by Bojan Miladinovic.
In the group's other game, a late goal by Abdul Kaider Keta saw Al Sadd snatch a 1-1 draw at Esteghlal.
The host had gone in front midway through the first half at the Azadi Stadium when Farhad Majidi was on hand to lash home following a poor clearing header.
However, Al Sadd levelled two minutes from the end when Nadir Belhadj's low cross was deflected and Keita headed home from inside the six-yard box.
In Group A, Sepahan sprung a surprise with a 2-1 victory at last season's semi-finalist Al Hilal.
The visitor took the lead in the 51st minute at King Fahd International Stadium when Ibrahima Toure headed home at the far post and extended that advantage nine minutes later when Al Hilal keeper Abdullah Alsdairy turned Fabio Januario's corner into his own net.
Christian Wilhemsson pulled a goal back late on for the host but it was not enough to prevent it crashing to defeat.
The other game in the group saw Al Jazira and Al Gharafa play out a stalemate at Mohamed Bin Zayed Stadium.