With his chiselled arms, onstage swagger and innuendo-laced tunes, one thing was clear - Shawn Mendes has come a long way since his early days as a fresh-faced teenager singing snippets of cover songs on now-defunct video-sharing app Vine.

The Canadian pop heart-throb, who turned 21 in August, had the packed, sold-out Singapore Indoor Stadium crowd of mostly teenage girls swooning over almost every song in his 105-minute set.

When they were not screaming themselves hoarse, the fans were singing along to his set list, whether it was gigantic hits such as Treat You Better (1.4 billion views on YouTube) or album cuts such as the funky, Prince-like Particular Taste.

Unlike his pop peers, whose music tends to skew towards a synthesizer and drum machine-driven sound, Mendes' live repertoire took on a more organic, old-school approach.

Hence the standard backing band set-up comprising guitars, bass and drums. Mendes, dressed in a sleeveless white shirt and skinny black jeans, would sling an assortment of guitars or play on pianos as he switched between the main stage and a smaller platform in the middle of the audience with a giant white rose as a prop.

There were some classic rock vibes in the smoke machine stage effects and his guitar solos on songs such as the ballad Ruin.

His singing was in fine form, especially in Nervous, a song in which he flawlessly executed vibratos and falsettos.

But while he alluded to steamy situations in tunes such as Where Were You In The Morning? and Bad Reputation, the concert was pretty much a PG affair, with nothing too edgy or explicit.

Always smiling and occasionally sweeping back his floppy fringe, Mendes, who previously performed in Singapore in 2017, seemed genuinely thrilled to be up on stage.

The singer, who got a new tattoo of the phrase "Good Luck" in a Singapore tattoo parlour in Haji Lane a day earlier, endeared himself to the fans with standard onstage flattery ("I think this is the loudest crowd in the tour").

Probably very much aware of the headline-hogging nature of his current relationship with fellow pop singer Camila Cabello, he teased a brief line from their current hit, Senorita, before launching into another of their duet, I Know What You Did Last Summer.

Perhaps as a nod to his Vine days, Mendes slipped in a couple of cover tunes, piano versions of Whitney Houston's I Wanna Dance With Somebody (Who Loves Me) and Coldplay's Fix You.

He did not have to - original hits such as the ultra-catchy Stitches and rousing mental health anthem In My Blood were more than enough to get the fans' heartbeats racing.