SM Entertainment's starlet group aespa held its first-ever concert under the banner of "Synk: Hyper Line" over the weekend at Jamsil Arena in Seoul Olympic Park.

It was a long-awaited first concert happening over two years after the group's debut in November 2020, and a much postponed return amid the ongoing internal feud of SM's management.

But the two nights of majestic spectacle proved that the wait was more than worth it, and only made the audience wonder what more potential the girl group could have to show in the future.

Sunday evening saw another 5,000 fans crowd into the indoor venue. For the second Seoul gig, global fans in 79 countries tuned in via online livestream platform Beyond Live, SM said.

As Karina, Winter, NingNing and Giselle appeared on the stage Sunday evening clad in brilliant white dresses, the indoor venue erupted in cheers.

The show kicked off loudly with "Girls," the title track from the act's latest second EP. Winter grabbed the spotlight with her mesmerizing solo electric guitar performance on the lifted stage. Winter had practiced until her fingers bled, her bandmates later explained.

With not a moment to spare, the act next performed a relay of three songs from its first EP "Savage" -- "aenergy," "I'll Make You Cry" and mega-hit lead single "Savage."

As it was the act's second night, the band seemed much more comfortable speaking with fans from the stage.

Winter cracked a few jokes, saying, "Unfortunately for you guys, you missed out on the fun part watching how awkward we were yesterday," adding, "It wasn't easy yesterday but we're in much better shape tonight."

According to the act's previous explanations on their avatar-themed futuristic concept, the four of them each have an artificial intelligence-powered avatar character who they can connect with through the virtual platform Synk.

The title of the concert, "Hyper Line," refers to the world where aespa, ae (the AI avatars) and My (the act's official fandom) come together, according to the band.

"In the online space, aespa and ae meet, and in the offline space, aespa and My meet," Winter elaborated.

In keeping with the act's concept, the night showcased a wonder of cutting-edge technology to bring aespa's virtual world to life. Making the magic happen was a transparent organic light-emitting diode screen upon which the four avatars appeared, moving in harmony with their human correspondents. Aespa originally officially debuted as a group of eight, including the avatars, but failed to keep the concept going.

The whole night felt like a surprise gift package for aespa fans, as the band unveiled 11 new songs -- nearly half of the 25 tracks performed each of the two nights.

Four of the new songs were solo tracks for each of the individual members.

Karina's "Menagerie," for which the singer took part in writing the lyrics, is a song about a zoo of exotic animals threaded together with the act's concept of "Hallucination Quest." Winter made the night's rare ballad moment with "Lips" -- her confession of love to the fans -- while Giselle with "2Hot4U" and NingNing with "Wake Up" each electrified the crowd with powerful performances.

Other new songs unveiled during the shows were "Thirsty," "Salty & Sweet," "I'm Unhappy," "Don't Blink," "Hot Air Balloon," "YOLO" and "Till We Meet Again."

For just their second standalone concert, the girl group dominated the stage Sunday, blazing through old and new songs alike.

Ears became nearly numb from the explosive cheers and screams from fans during the performances of the act's megahits "Savage," "Illusion," "Next Level" and "Black Mamba," while hidden gems "Lucid Dream," "Dreams Come True" and "Life's Too Short" opened eyes to the unforeseen charms of the group.

Not only fans, senior artists of SM Entertainment including Taeyeon, Changmin and members of Red Velvet, Super Junior, SHINee and NCT attended Sunday's gig to show support for the rookies' new start. Their presence was especially heartwarming as SM artists strive to maintain their career amid the ongoing management wrangling between the company, its founder Lee Soo-man and industry rival Hybe.

Bidding farewell to the audience, aespa performed "Till We Meet Again" and "ICU" for the encore.

"We had so much fun tonight. Thank you so much. The air was different tonight from yesterday, and I felt we were more comfortable and Mys had more of the 'yolo' vibe. Let's have more fun next time," Giselle said.

"I was so happy yesterday and today. I hope we could always stay together. Thank you everyone. We'll also work hard on the rest of the tour," NingNing said.

Shouting out global fans watching in real time through Beyond Live, Karina said, "We'll bring much more new content with a comeback, so please look forward to it. We'll continue to improve as artists, and we've never let you down on promises we've made before, so please stay with us."

Meanwhile, aespa was reportedly slated to return Feb. 20 with a new album, but had the schedule postponed at the last minute. Fans and industry insiders have assumed the ongoing company feud is behind the delay.

With the Seoul concerts as a start, aespa's "Synk: Hyper Line" continues around the world, making its next stop in Japan's Osaka on March 15.