Daejeon Hana Citizen FC players celebrate their 2-1 victory over Ulsan Hyundai FC in a K League 1 match at Daejeon World Cup Stadium in Daejeon, 140 kilometers south of Seoul, on Sunday. (Yonhap)

Seven matches into their first season in the top South Korean football league since 2015, Daejeon Hana Citizen FC are making serious noise.

Daejeon defeated K League 1-leading Ulsan Hyundai FC 2-1 at home Sunday, halting Ulsan's win streak at six matches. With one more win, Ulsan, the defending K League 1 champions, would have tied the league record for the most consecutive victories to kick off a season.

Instead, Daejeon made sure they wouldn't allow Ulsan to celebrate a win on their home turf. With Lee Jin-hyun and Lee Hyun-sik scoring for Daejeon, Ulsan allowed more than one goal in a match for the first time this year.

Ulsan remained in first place at 18 points from six wins and a loss. Pohang Steelers, now the only remaining undefeated team this year with four wins and three draws, sit in second place with 15 points. They had a 1-1 draw against FC Seoul on Saturday.

Daejeon are in third at 14 points from four wins, two draws and a loss. They have not lost at home this season, with three wins and a draw.

Daejeon earned their promotion from the K League 2 for this season. They hadn't been in the top competition since 2015, and at this rate, they likely won't have to worry about being relegated this year. Daejeon now lead the K League 1 with 16 goals, two more than Ulsan.

Also in the K League 1, Jeonbuk Hyundai Motors suffered a 1-0 loss to Suwon FC on Saturday, as their underwhelming season continued and the temperature on head coach Kim Sang-sik's hot seat went up a few notches.

Jeonbuk are in ninth place among a dozen clubs with two wins, one draw and four losses for seven points. They lost just seven times in 38 matches all of last year, while finishing in second place to Ulsan.

The league's two bottom-feeders remained without a win this year after the weekend. On Saturday, Suwon Samsung Bluewings lost to Jeju United 3-2, suffering their fifth defeat in their first seven matches this season. They occupy last place in the 12-team league with two points.

Gangwon FC dropped to Incheon United 2-0 on Sunday for their fourth loss in seven matches this year, along with three draws. (Yonhap)