"Everything went as well as we planned," said Seo in post-match press conference. "I'm happy that our players have gained confidence through this match."

This was only Suwon's second win this season in all competitions. They are still winless in the K League Classic with four draws and one loss.

Suwon's next AFC Champions League match is against Kawasaki on April 25 at home. The two clubs played to a 1-1 draw in their previous meeting.

"We still have two more matches left and we need to play well against Kawasaki at home," he said. "We want to clinch a place in the round of 16 by winning that match."

Against the ACL debutants Eastern, Suwon almost gave up the lead just five minutes into the match. Jaimes McKee curled a right-footed shot after intercepting a pass from Koo Ja-ryong, but

Suwon goalkeeper Yang Hyung-mo parried it away for a corner.

Suwon then started to show their firepower as captain Yeom Ki-hun and Brazilian forward Santos kept knocking on Hong Kong club's door. Yeom had an uncontested shot from the center of the box in the 14th minute that went too high, while Santos' left-footed effort hit the left side of net five minutes later.

They finally opened the door in the 37th minute. Park Gi-dong's left-footed shot from outside the box was denied by Eastern goalkeeper Yapp Hung-fai, but Ko Seung-beom picked up the rebound and delivered a fine cross for Yeom to finish with a header.

Suwon made its first substitution in the 54th to boost their attack, as Croatian attacker Damir Sovsic came on for Ko Cha-won.

The hosts doubled the lead in the 63rd when Ko Seung-beom blasted a right-footed strike that found the bottom left corner of the net.

It was Ko's first goal in his professional career since making his debut in 2015.

Johnathan replaced Yeom in the 72nd and it just took four minutes for the Brazilian to score twice. Johnathan first fired a right-footed shot for a 3-0 lead in the 74th and picked up his fourth goal of the tournament two minutes later after receiving a pass from Santos.

The South Korean club, however, wasn't done for the night, as Ko Seung-beom again put his name on the score sheet with his right-footed effort in the 79th.

Eastern, led by female coach Chan Yuen-ting, failed to unlock Suwon's defense in three minutes of added time.

Elsewhere, another South Korean club, Ulsan Hyundai, lost 1-0 to Thai champions Muangthong United in their Group E contest on the road.

Ulsan, the 2012 ACL champions, surrendered the match's only goal to Teerasil Dangda in the 37th at Thunderdome Stadium in Nonthaburi, Thailand, and picked up their second loss in the group. Earlier in the day, Brisbane Roar beat Kashima Antlers 2-1 in their Group E match.

Ulsan and Brisbane are now tied at four points with one win, one draw and two losses, but the South Korean club remained in third place thanks to the superior head-to-head record. Ulsan previously blanked Brisbane 6-0.

Muangthong moved to the top spot in Group E with the latest victory. They have two wins and two draws for eight points, two points above Kashima.

Ulsan will next host Kashima on April 26. The South Korean club fell 2-0 to the Japanese champions in their first meeting in February. (Yonhap)