278/3 by Afghanistan (vs Ireland at Dehradun on 23rd February 2019)
After deciding to bat first, Afghanistan batsmen dominated in that game to settle the record-breaking T20I total, which led them to win that game comfortably.
Afghan openers Hazratullah Zazai and Usman Ghani set the record opening partnership of 236 runs, which helped them hugely to create a history. While Ghani scored 73 runs off 48 balls (7 fours and three sixes), Zazai completed his century in just 42 balls and remained not out on 162 runs off just 62 balls (11 fours and 16 sixes) – the second-highest individual T20I knock.
While Afghanistan scored 278/3 (20 overs) in the first innings, Ireland managed to score 194/6 (20 overs). So, Afghanistan won that game by 84 runs.