I.O.I‘s reunion title track “Suddenly” has made K-pop history by breaking an eight-year record previously held by BLACKPINK’s iconic hit “DDU-DU DDU-DU.” The song has now spent 31 consecutive days at No. 1 on the MelOn Daily Chart, making I.O.I the third-generation girl group with the longest-running No. 1 streak in the chart’s history.

“Suddenly” recently reached another major milestone by extending its reign atop the MelOn Daily Chart to 31 consecutive days. The achievement officially surpasses the record set by BLACKPINK’s 2018 smash hit “DDU-DU DDU-DU,” which remained at No. 1 on the MelOn Daily Chart for 30 straight days. BLACKPINK’s record stood unchallenged for nearly eight years (2,906 days) before I.O.I finally overtook it.

With this accomplishment, I.O.I now holds the record for the longest MelOn Daily Chart No. 1 run by a third-generation girl group.

Released in 2018 as the title track from BLACKPINK’s mini album Square Up, “DDU-DU DDU-DU” became one of the defining K-pop hits of its generation. Just two hours after its release, the song achieved an All-Kill by topping seven major Korean music charts. It later earned a Perfect All-Kill on iChart, dominated the Gaon Digital Chart for three weeks, and remained in the Top 100 for more than 50 weeks.

On MelOn, it spent 30 consecutive days at No. 1 on the Daily Chart, a benchmark that had remained untouched among third-generation girl groups for years. The music video also became one of K-pop’s most iconic releases, surpassing 2.3 billion views on YouTube. Given the legendary status of “DDU-DU DDU-DU,” “Suddenly” breaking its MelOn record has drawn widespread attention from K-pop fans.

“Suddenly” serves as the title track from I.O.I’s reunion mini album I.O.I: LOOP, released to celebrate the group’s 10th debut anniversary. The album was released on May 19, marking the long-awaited reunion of the beloved Produce 101 Season 1 project group.

Despite the excitement surrounding the reunion, the song did not become an instant success. Some listeners criticized its retro synth-pop sound as being outdated compared to current K-pop trends, while others felt the music video lacked the scale and production value expected from such a highly anticipated comeback. The song also debuted modestly, entering the MelOn TOP100 at No. 100 upon release.

Everything changed once I.O.I began promoting the song through music show performances and public appearances. “Suddenly” steadily climbed the charts—from outside the upper rankings into the Top 10 before eventually challenging for the top spot.

By 8:00 a.m. KST on May 29, the song had achieved its first Real-time All-Kill, simultaneously topping all of Korea’s major real-time music charts, including MelOn, Genie, FLO, and Bugs. Since then, it has maintained remarkable momentum, holding onto the No. 1 position on the MelOn Daily Chart for 31 consecutive days.

The achievement highlights I.O.I’s lasting popularity despite the group’s remarkably short original career. Formed through Produce 101 in 2016, I.O.I quickly became one of South Korea’s most beloved girl groups before disbanding in early 2017 after less than a year of promotions. Even so, the group left behind a string of memorable hits, including “Dream Girls,” “Whatta Man,” “Very Very Very,” and “Downpour.”

Interestingly, this is not the first time I.O.I has edged past BLACKPINK in a notable milestone. At the 2016 MAMA Awards, I.O.I won Best New Female Artist, while BLACKPINK was also among the most talked-about rookie groups that year. Nearly a decade later, the two third-generation girl groups are once again being compared this time because I.O.I has broken a chart record that BLACKPINK held for almost eight years.

I.O.I’s reunion was organized as a full-fledged 10th anniversary project, featuring the release of the mini album I.O.I: LOOP, promotions for “Suddenly,” and the I.O.I: LOOP concert tour. Following the conclusion of their Hong Kong concert, the group wrapped up its anniversary activities after delivering new music and reunion performances that exceeded the expectations of many fans.

From a project group that originally promoted for less than one year, I.O.I has once again demonstrated its enduring influence. The 31-day No. 1 streak on the MelOn Daily Chart stands as clear proof that the group’s music continues to resonate with the Korean public a decade after its debut.

After ten years, I.O.I remains one of K-pop’s most recognizable third-generation girl groups. The success of “Suddenly” not only showcases the group’s lasting appeal but also cements its place alongside the biggest names of its generation, especially after surpassing the long-standing MelOn record set by BLACKPINK’s global hit “DDU-DU DDU-DU.”

Sources: K14