Pohang Steelers began the defence of their AFC Champions League title with a surprise 1-0 loss to bogey side Adelaide United in their Group H opener.

19-year-old Socceroo Mathew Leckie scored on the stroke of half-time after running 80 metres with the ball.

Newly crowned Saudi champions Al Hilal confirmed their reputation as the team to watch in the west when they beat Al Sadd 3-0 in Doha, where Saudi Arabia striker Yasser Al Qahtani scored a brace and Brazilian Thiago Neves netted in injury time.

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Kashima Antlers, Jeonbuk Motors and Beijing Guoan, reigning champions of Japan, Korea Republic and China respectively, were among the east-zone winners in the opening round of group-stage matches. Uzbek champions Bunyodkor and reigning Iran Pro League winners Esteghlal were among the winners in the west.

Leckie was called up to the Australia squad by Pim Verbeek last week after only his first season in the A-League and continued a memorable month with a remarkable goal.

After bravely winning a header outside his box following a Pohang corner, the speedy teenager sprinted to the Pohang box where he turned inside Shin Hyung-min and Kim Kwang-suk before an attempted clearance by Park Hee-chul deflected off Leckie's outstretched leg into the goal.

"He can sometimes fight with the ball technically, but he's got raw speed and aggression, and he puts defenders on the back foot. He's a terrific prospect," said Joe Mullen, Adelaide's temporary head coach.

"To get the goal right at the death of half-time was a perfect time to score and that was just through sheer endeavour, commitment and tenacity from Leckie. It mirrored the performance of the whole team. The players were fantastic."

Mullen praised new signings Marcos Flores of Argentina and Dutch striker Sergio van Dijk after a victory that continued Adelaide's recent revival following back-to-back wins at the end of a disappointing domestic season, where they finished bottom of the A-League.

"Certainly the last couple of games in the A-League gave them that belief and they took that into the game," Mullen said. "Flores has certainly got that flair that was probably missing in the A-League. You can see Van Dijk is quality. He puts himself in dangerous positions."

It was a disappointing AFC Champions League debut for new Pohang boss Waldemar Lemos, who fielded Brazilian signings Alexandro and Mota up front, while Korea Republic internationals No Byung-jun, Kim Jae-sung, Shin Hyung-min and Kim Hyung-il returned after extended international duty.

"I wanted to play offensively when we went a goal down, but they didn't let us," said the Brazilian, younger brother of Kashima coach Oswaldo Oliveira. "There were a lot of fouls. I know Australia's style, but I don't like this (waiting for Pohang to make mistakes). Adelaide have good players, this you can see."

Shandong Luneng, Chinese Super League winners in 2006 and 2008, joined Adelaide on three points after beating first-timers Sanfrecce Hiroshima 1-0 in Japan, with China striker Han Peng heading home a corner in the 77th minute.

Suwon Bluewings and 2008 champions Gamba Osaka played out a scoreless draw in Group G, a scoreline matched by debutants Henan Jianye and Singapore Armed Forces in Zhengzhou.

In Group E, Australian striker Joel Griffiths finished a brilliant passing sequence as Beijing beat Melbourne Victory 1-0 in front of 31,000 fans at the Workers Stadium. The 'Imperial Guard' are under great pressure to improve on last year's campaign when also won their opening match, against Australian opposition, before finishing bottom of their group.

Seven-time K-League champions Seongnam Ilhwa lead the group after a 2-0 home win over Japan's Kawasaki Frontale, quarter-finalists in 2007 and 2009, with goals from former Colombia striker Mauricio Molina and towering target man Dzenan Radoncic of Macedonia.

In Group F, Kashima beat Changchun Yatai 1-0, Koji Nakata heading home from Fellype's 42nd-minute free-kick, while Jeonbuk crushed Persipura Jayapura 4-1 in Jakarta, with new Croatian signing Kruno Lovrek scoring a hat-trick for the Greens after coming on as a first-half substitute.

In the west, Al Hilal, who secured the 2009-10 Saudi league title last month and won the Crown Prince Cup last week, consolidated their reputation as one of the pre-tournament favourites with a 3-0 win over Sadd that put Eric Gerets' men top of Group D.

"Three goals, away game, I'm happy. We now have two games at home and playing in front of our own supporters will help us," said the former Marseille boss, who has won the Belgian, Dutch and Turkish leagues as a coach.

"The AFC Champions League is our top priority. We've achieved 60 per cent of our goals for this season and now we're looking at the remaining 40 per cent. We know we're facing tough teams in this group, but we're ready," added Gerets, Belgium's second most-capped player.

Iranian first-timers Mes Kerman are also on three points after beating UAE champions Al Ahli 4-2, with former Iran striker Mahdi Rajabzadeh bagging a brace in the final 15 minutes to help the hosts rally from 2-1 down.

Pakhtakor, the only club to have competed in all eight editions of the AFC Champions League, lead Group C after beating Al Ain 1-0 in the UAE, where Artur Gevorkyan scored for the eight-time Uzbek champions.

Al Shabab, currently second in the Saudi league, drew 1-1 with Iran Pro League leaders Sepahan after a 69th-minute equaliser by striker Fisal Bin Sultan cancelled out Seyed Jalal Hossein's brave diving header in the 14th minute.

In Group B's headline clash on Tuesday, Brazilian legend Rivaldo turned back the clock when he curled a 20-yard shot into the top corner in only the third minute of Bunyodkor's 3-0 win over Al Ittihad, last year's finalists and winners in 2004 and 2005. Uzbekistan winger Jasur Hasanov bundled in a second in the 21st minute and Denilson headed home in the 66th minute to score his first competitive goal for his new club after helping Pohang win the title last year.

Igor Castro scored arguably matchday one's best goal with a stunning effort in Zobahan's 1-0 win over Al Wahda in Esfahan, where the Brazilian received the ball on the right touchline five yards inside his own half before dribbling to the edge of the area and unleashing a left-foot piledriver.

In Group A, Esteghlal captain Farhad Majidi scored with two headers to power the Blues to a 2-1 win over Al Ahli in Jeddah, where substitute Hassan Al Raheb scored a late consolation. Qatari champions Al Gharafa won 2-1 at Al Jazira in Abu Dhabi, where Moroccan midfielder Otman El Assas and Iraq striker Younus Mahmood scored before Brazilian forward Rafael Sobis pulled one back.

Matchday Two will be held on Tuesday, March 9 and Wednesday, March 10.