Posting 235-5 in their 20 overs, Ireland recorded the highest total of the tournament so far, surpassing the 225-5 made by Sri Lanka national cricket team against the same opposition earlier in the competition.
The innings was built on a remarkable late surge that yielded 86 runs from the final four overs.
Captain Lorcan Tucker, leading in place of the injured Paul Stirling, anchored the recovery with an unbeaten 94 off 51 balls, striking 10 fours and four sixes. He shared a decisive fifth-wicket stand of 101 from 56 deliveries with Gareth Delany, who hammered 56 off 30 balls.
Ireland had slumped to 64-4 in the eighth over after Shakeel Ahmed (3-33) ripped through the top order in the powerplay, dismissing Tim Tector (5), Ross Adair (14) and Harry Tector.
The onslaught intensified as Shah Faisal, Mohammad Nadeem, Jiten Ramanandi and Sufyan Mehmood were punished heavily at the death.
George Dockrell then blasted 35 not out off just nine balls, launching five sixes, including from the final three deliveries.
Oman's reply faltered despite Aamir Kaleem's 50 off 29 balls. They were 97-2 in the 11th over before collapsing, losing seven wickets for 24 runs. Josh Little (3-16) and Barry McCarthy (2-32) sealed the win as Oman were bowled out for 139 in 18 overs.
Ireland, beaten previously by Sri Lanka and Australia, can still reach the Super 8s if they defeat Zimbabwe in Pallekele and other results favour them.
Oman, meanwhile, are eliminated after three straight losses and will face Australia in their final fixture.
Australia's Matt Renshaw expressed his disappointment after the shock loss to Zimbabwe at the T20 World Cup on Friday, saying his team should have chased down the 170-run target.
The United States delivered a commanding performance to defeat the Netherlands by 93 runs in Chennai on Friday, keeping their slim hopes alive of repeating their Super Eight run from two years ago in the ICC Men's T20 World Cup 2026.
UAE recovered from 66-4 to chase down a target of 151 to beat Canada by five wickets to register their first victory at this year's T20 World Cup in Delhi.
Ireland captain Paul Stirling has been ruled out of the rest of the 2026 T20 World Cup due to injury.
