Michael Leask smashed a brilliant 91 not out to lead Scotland to a dramatic one-wicket victory over Ireland from the final ball at the World Cup Qualifier on Wednesday.
Scotland were reeling at 152-7 in the 34th over, chasing 287 to win in Bulawayo, but Leask struck 91 from 61 balls to clinch a win to start their campaign.
Ireland, though, are on the brink of failing to reach a second straight World Cup after suffering a second successive Group B defeat after their opening loss to Oman.
Two teams from the 10-nation event in Zimbabwe will qualify for the main tournament to be held in India in October and November.
"We've had a few tough games against Ireland, so to get this against them is even more special," said Leask, who was part of the side beaten by Ireland in the last World Cup Qualifier five years ago.
"We've got a great bunch of lads and this is just the start of our journey. This is how we'll play our cricket, we'll take things deep."
Scotland are hoping to right the wrongs of the previous qualifying tournament in 2018, when they missed out on the World Cup in England and Wales as a controversial lbw decision and untimely rain saw them slip to an agonising defeat by the West Indies.
Ireland also failed to qualify on that occasion, having reached the three previous World Cups.
"The first 10 overs when we were batting and the last 10 overs when we were bowling took the game away from us," said Irish captain Andy Balbirnie.
"We'll lick our wounds here and go again next game."
Oman lead the early group B table, with three of five teams to reach the Super Six stage, after notching a second win from as many games with a five-wicket success against the United Arab Emirates.
- Campher stars -
Ireland were struggling at 70-5 after being put in to bat first as Brandon McMullen removed Paul Stirling, Balbirnie and Harry Tector with the new ball.
But Curtis Campher hit back with a magnificent 120 from 108 balls, aided by George Dockrell's 69.
McMullen finished with 5-34 from seven overs as the Irish posted 286-8 from their 50 overs.
Scotland made a solid start to their chase but the loss of Christopher McBride, trapped lbw by Campher for 56, started a collapse of four wickets for 32 runs from 90-2.
The Scots were still 135 runs away from victory when Chris Greaves fell to Dockrell for 20, but Mark Watt joined forces with Leask in an 82-run stand for the seventh wicket.
Scotland eventually needed eight from the final over bowled by Mark Adair with two wickets in hand and looked set to win when Tector's poor misfield gifted Leask a four from the first delivery.