It’s the end of Brat summer as we know it and we all feel fine. Charli xcx’s exclusive headline slot is the major drawcard for the 20th year of St Jerome’s Laneway festival, as the British hyperpop star runs a victory lap for her Grammy-winning album, Brat. At the first leg of the Australian festival, a sold-out Brisbane Showgrounds is teeming with punters bedecked in the album’s signature lime green.

It’s a victory lap of sorts for Laneway, too, one of the last festivals of its kind in a rapidly shrinking Australian live landscape (last month, Splendour in the Grass and Groovin the Moo were both canned for the second year in a row). What started as a small boutique event in an inner-city Melbourne laneway now boasts crowds of tens of thousands, and tours around the country and even overseas. It feels like what the Big Day Out once was but for a new generation, and the very young crowd reflect that. The downside is that Laneway’s personality now feels diluted – it has become a festival for the masses. What was once an opportunity for punters to discover new, smaller artists has shifted towards a smorgasbord of who’s hot right now, particularly online.

The influence of social media is strongly felt at the festival, epitomised in Djo’s set. The Stranger Things actor gets a largely muted response until his final song, End of Beginning – which was a viral TikTok sound in snippet form – sends the crowd wild and has phones up in selfie mode as punters take videos, presumably to also upload to the app. It’s emblematic of how the younger generation interacts with music now but feels jarring to witness – how this might play out in years to come remains to be seen.

But the past is always present: gen Z’s fascination with nostalgia is evident in some of the acts, including the US shoegazers Julie, all in their early 20s but playing a brand of fuzzed-out rock that sounds straight from the 90s. The band has an early slot as the blazing sun beats relentlessly down and their walls of distortion awaken the crowd.

Later Clairo’s sunset set crackles as though it’s spinning on an old record player, though the US singer-songwriter – also a festival exclusive – struggles to be heard above an uneven, bass-heavy sound mix. This isn’t the best setting for her introspective, 70s-inspired music but she’s a charming performer – fitting as the set is mostly made up of songs from her latest album, Charm, with intricate instrumental arrangements. Live, Clairo’s band includes clarinet and a rousing saxophone solo on Sexy to Someone; the older track Bags taps into an indie-rock vibe that’s more suited to a large festival. This is carried on in Beabadoobee’s later set, which feels both intimate and expansive.

Olivia Dean feels like a companion: smooth, soulful tunes delivered with style, providing a more chilled-out experience than the festival’s otherwise EDM-heavy lineup. It’s particularly moving when the British singer dedicates a track, Carmen, to her grandmother.

Joccy’s stage is one of the only undercover areas of the festival, providing respite from the sun but heating up quickly with dancing bodies – it’s reminiscent of the BDO’s Boiler Room. Melbourne’s Rona is an early highlight, spinning tracks with seamless transitions against a flashing red Indigenous flag. A remix of Ojax’s Act a Fool has the crowd roaring and Rona looks as though she’s having a blast too as she throws shapes on stage.

The Pennsylvania hip-hop duo Joey Valence and Brae, on the rapid rise, drop an incredibly fun remix of Charli xcx’s 365 alongside their own high-energy tracks including The Baddest and Freaks, creating a sweaty sea of hands. Ninajirachi keeps the party going between sets all afternoon with an interstitial soundtrack of remixed pop hits.

The last time Charli xcx appeared at Laneway, in 2020, she was still somewhat of an underground favourite – now she’s ascended to become the queen of the cultural zeitgeist with a record that’s equal parts fun and intelligent.

The venue transforms into an open-air club for a joyous 70 minutes as she blazes through tracks from Brat, with a few older songs thrown into the mix (the moving Track 10 is a highlight) and the requisite silly songs about fast cars (Vroom Vroom, Speed Drive). Unlike most other pop stars playing stadium shows, Charli is alone on stage. She doesn’t need anyone else – she’s larger than life, prowling at the camera closeup and making good use of the tiered stage. The TikTok phenomenon is present in this set too, with the singer encouraging fans to perform the viral Apple dance, created by a fan. It adds to the fun. I Love It, Charli’s 2012 collaboration with Icona Pop, now feels passe among her more adventurous catalogue but it’s the perfect singalong to end the night.

The rapturous crowd proves that there is still a huge appetite in Australia for the festival experience, particularly among the younger generation who are hungry for the community and euphoria that only live music can bring. Let’s hope this is a sign of better things to come.

• Laneway continues in Sydney, Melbourne, Adelaide and Perth until 16 February