The K-pop girl group kick off the new decade as the first track to top World Digital Song Sales and join an elite group of artists.

Red Velvet are kicking off the decade at the top.

The K-pop girl group see their new single "Psycho" debut at No. 1 on Billboard's World Digital Song Sales chart after selling 2,000 downloads in the week ending Dec. 26 in the U.S., according to Nielsen Music. While it's a strong start, the act's biggest week for a song was last year when "Bad Boy" debuted with 4,000 downloads sold, which landed them at No. 2 on the World Digital Song Sales chart dated Feb. 10, 2018.

The R&B-pop track follows 2018 single "RBB (Really Bad Boy)" as Red Velvet's only other chart-topper on World Digital Song Sales putting them in an elite group of K-pop artists with more than one single to hit No. 1. Altogether, Red Velvet is just the ninth K-pop act to grace the top of World Digital Song Sales more than once (joining a group that includes the likes of PSY, BIGBANG, EXO, BTS and J-Hope) and fourth K-pop girl group to do so (after 2NE1, BLACKPINK and TWICE).

Red Velvet has logged 20 entries on World Digital Songs throughout their career starting with 2014's "Happiness" which peaked at No. 4 on the chart. When it comes to Red Velvet's top-selling songs in America, their best-seller is "Bad Boy" with 27,000 copies sold in America to date, according to Nielsen Music. It's closely followed by 2015's "Dumb Dumb" (with 26,000 sold), then 2016's "Russian Roulette" (24,000 sold), 2015's "Ice Cream Cake" (23,000) and 2017 single "Peek-a-Boo" (21,000).

As the final single released from Red Velvet's ReVe Festival trilogy of EPs, "Psycho" marks a satisfying conclusion to the girl group's year of experimenting. The ReVe Festival, Day 1 EP saw the group bending genres with the electro-house single "Zimzalabim" (which peaked at No. 10 on World Digital Song Sales) and a host of excellent b-sides, before going to a more sunny, traditional-pop side with The ReVe Festival: Day 2 and the feel-good summer single "Umpah Umpah" (which peaked at No. 9). Ultimately, it feels like U.S. fans respond best the group add some R&B flavor to their sound as "Psycho" feels like a worthy companion to best-seller "Bad Boy" with a minimalist, snappy beat leading to a surge of harmonies on the chorus.

Elsewhere on the charts, Red Velvet see their new The ReVe Festival: Finale EP start at No. 6 on World Albums, which is mostly in line with the performance of both The ReVe Festival, Day 1 (which peaked at No. 7) and Day 2 (which also peaked at No. 6). The RV ladies also remain at their peak position on the Social 50 chart to date, staying strong for another week at No. 2 just behind longtime chart leaders BTS.

While member Wendy is currently healing from serious injuries suffered after a fall during a rehearsal, Red Velvet did perform "Psycho" once together before tragedy struck. Take a look at the "Psycho" music video as well as a performance recorded at the SBS Gayo Daejeon below: