Uzbekistan's Bunyodkor provided the biggest upset of this year's fledgling AFC Champions League when they shocked J-League title-holders Sanfrecce Hiroshima 2-0 away on Wednesday.
Despite last year's run to the semi-finals the Uzbek cup-winners were considered underdogs against the Japanese champions, but a late goal in each half made them worthy winners in Hiroshima.
Oleksandr Pyshur struck on the stroke of half-time to put the visitors ahead but it wasn't until the 86th minute that Bunyodkor could be sure of the win, when Fozil Musaev doubled their advantage.
The victory extends Bunyodkor's fine form in the Asian competition after they overturned three former champions last year before being halted by eventual winners Ulsan Hyundai in the last four.
Elsewhere on day two, Kashiwa Reysol registered the first Japanese win when ex-Guangzhou Evergrande striker Cleo, returning to China to face Guizhou Renhe, was on target in the first half to secure a 1-0 victory.
The 2009 winners Pohang Steelers were held 0-0 by Beijing Guoan and Australia's Central Coast Mariners and Suwon Bluewings also finished goalless.
In a frantic finish in Pohang, Beijing midfielder Joffre Guerron fired against the crossbar. For the Steelers, Kim Won-Il missed a golden chance and Hwang Jin-Sung twice went close with headers, but nobody could break the deadlock.
Earlier the Mariners, Australia's only team in the competition, looked sure to secure all the points at their home ground in Gosford when Kwak Kwang-Seon handled inside the box in the final minutes.
However, Nick Montgomery's effort was saved, leaving it all square after the Mariners failed to capitalise on a number of chances against the 2011 semi-finalists.
Iranian champions Sepahan cruised to a 3-0 win over Al Nasr of the United Arab Emirates with Albanian striker Xhevahir Sukaj scoring twice and Omid Ebrahami adding a third with four minutes remaining.
Saudi Arabia's Al Ahli also enjoyed a winning start in Group C, beating Al Gharafa of Qatar 2-0.
In Group D, UAE side Al Ain, the inaugural winners of the tournament in 2003, came back from a goal down to defeat 10-man Saudi outfit Al Hilal 3-1 with Australian striker Alex Brosque and Ghana star Asamoah Gyan amongst the scorers.
"Al Ain had a big game and we showed the good level of UAE football against a big team like Al Hilal," said Al Ain boss Cosmin Olaroiu, a former Al Hilal coach.
In Doha, Al Rayyan shared a six-goal thriller with the Qataris coming back three times for a share of the spoils against Esteghlal of Iran.
The pan-Asian league, now entering its second decade, features 32 teams from 10 different countries. The group phase ends in early May but the two-legged final will not take place until November.