Tens of thousands of fans descended on the Irish capital for the first of two sold-out gigs at the country's largest stadium.
The 90s Britpop superstars performed to 80,000 people at Croke Park on Saturday and are scheduled to do the same on Sunday night.
Health officials had advised revellers to wear their bucket hats, with high UV levels predicted.
As the band's first gig in the country since 2009, the Dublin leg of the reunion world tour holds a special meaning for once-feuding brothers Noel and Liam Gallagher.
The Mancunian brothers have often spoken about their ties to Ireland through their Irish-born parents, Peggy and Thomas.
They display the image of an Irish harp as part of their comparatively understated stage decor.
In a regional change to the warm-up tunes, the crowd enthusiastically joined in singing as The Auld Triangle blared over the stadium speakers before the brothers walked out, as Fuckin' In The Bushes played for their entrance.
Liam also dedicated Roll With It to the people of Charlestown, County Mayo - where his mother hails from.
Mid-song, he also turned to the upper tiers where she was expected to have been sitting and blew kisses as he mouthed: "I love you".
Liam Gallagher told the crowd: "Oasis vibes in the area, Dublin vibes in the area."
The singer, who described himself as a "Croke Park virgin" because the band had never played there, added: "This is the soberest I've ever been in Ireland."
Acknowledging how fans have missed the presence of the band, Liam added: "You've been missed as well - you lunatics."
Fans said Dublin was "buzzing" for the reunion, with some comparing it to Christmas in August.
Sarah and Neil Charlton travelled from Southampton to see the band, after a determined search for standing tickets saw them clinching access in Dublin.
Charlton said they have both been waiting a long time to see the band reunite, having seen Oasis multiple times before their extended hiatus.
"It's just so nostalgic - all the songs and all the music from when we were growing up," Charlton said.
"When we first started seeing each other, we went to a gig and so it's always been a part of our lives together."
The highly anticipated 41-date run has already seen the band play Cardiff, Manchester, London and Edinburgh.
They are also headed to the US, Canada, Mexico, Australia and Japan.
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