Elsewhere, China's Shandong Luneng beat Japan's Cerezo Osaka 2-0 at home.
The match between Kashima Antlers and Sydney FC was postponed due to the earthquake and tsunami in Japan.
Suwon top Group H with two wins out of two after Ha Tae-Gyun hit a hat-trick.
The result was never in doubt after Ha put Suwon ahead early as the hosts dominated.
Oh Jang-Eun added a second before the break while two second-half goals from Ha sealed the win.
Suwon coach Yoon Sung-Hyo highlighted the importance of the early goal.
"We were able to get the win because we got an early goal," said Yoon.
"Ha Tae-Gyun and all the players did a good job."
Ha was stretchered off at the end of the match but the club is hopeful he will make a swift recovery.
Fellow Korean side Jeonbuk Hyundai Motors also scored four goals in their away tie against Arema Indonesia to move to the top of Group G.
Two goals from Luiz Enrique and one each from Huang Bowen and Kim Jee-Wong did the damage against Arema, who were competitive throughout the clash.
Jeonbuk coach Choi Kang-Hee felt the win had not come easily, despite the one-sided outcome.
"Arema played really well in the first half," he said.
"But it all changed after the second goal. Our players relieved the tension. We could play better after we doubled our lead."
Meanwhile, first-half goals from Renato Silva and Wang Yongpo saw hosts Shandong Luneng pick up their first win in the 2011 competition with a 2-0 defeat of Cerezo Osaka in Group G.
The Chinese Super League champions, reduced to 10 men 10 minutes before the final whistle when Cui Peng was sent off, were the better side throughout and created plenty of chances.
Brazilian striker Renato Silva opened the scoring in the 22nd minute, stabbing home from close range after latching onto Han Peng?s header.
Wang doubled the advantage 10 minutes later.
Shandong Luneng boss Branko Ivankovic felt his side could have scored more goals.
"We could have produced a better result if the players had taken full advantage of the chances we created," he said.
In Wednesday's late matches, Qatari side Al Sadd pulled level with Saudis Al Nassr at the top of Group B after beating Uzbek outfit Pakhtakor 2-1.
Lee Jung-soo's superb volley for the hosts on the stroke of half-time was cancelled out by Temurkhuja Abdulkholiqov, but substitute Ali Arif's header four minutes later secured the points for Al Sadd.
"We are not celebrating getting four points from two games," warned Al Sadd coach Jorge Fossati, whose team drew 1-1 at Esteghlal in their group opener.
"We have to qualify for the next round. This is my mentality when I play this kind of competition."
Saudi giants Al Ittihad are now four points clear in Group C following a 1-0 win at the home of Uzbek champions Bunyodkor.
"To be honest, I did not expect that we could beat Bunyodkor in Tashkent," said Al Ittihad coach Toni, whose side prevailed through a 33rd-minute header from Osama Al Harbi.
"We are now in an excellent position in the group. This victory has significantly improved our chances of reaching the next round."
In the other group game, Iran's Piroozi Athletic drew 1-1 at home to Al Wahda of the UAE.
First-half goals from Nabil Daoudi and Hadef Al Zaabi earned Emirates a surprise 2-0 win at home to Qataris Al Rayyan in Group D.
The UAE representatives are now a point behind Iranian group leaders Zobahan -- last season's runners-up -- who drew 0-0 at Al Shabab of Saudi Arabia.