O’Brien evoked memories of his World Cup heroics against England in Bangalore in March 2011 in an innings that included 11 fours and two sixes, but Ireland had to settle for a tie.
In a game interrupted by four rain stoppages, Pakistan set a challenging revised target of 276, after posting an impressive 266-5 in their 47 overs.
Ireland were 261-5 after 46 overs, and needed a daunting 15 off the last over of the match, to be bowled by the world’s top-ranked ODI bowler Saeed Ajmal.
Man-of-the match O’Brien hit the fourth ball of the over for six to leave a target of seven runs from three balls, and then scampered two off the fifth to leave five runs needed off the final ball.
O’Brien recalled one of the greatest moments of Irish cricket as he talked with non-striker Trent Johnston out in the middle ahead of that final Ajmal delivery.
It was he and Johnston, after all, who were at the crease to lead Ireland to that memorable victory against Pakistan in the 2007 World Cup.
Johnston hit a six off Azhar Mahmood at Sabina Park to win that game, and reminded O’Brien of the fact as the Railway Union all-rounder set himself to face Ajmal’s final delivery.
“Trent mentioned it before the final ball and asked: ‘How about you hit the winning runs this time?’” O’Brien said.
Ajmal’s ball was on leg stump, and O’Brien was able to nudge the ball past square leg for a four to tie the scores.
And he said he was disappointed Ireland could not close out the win.
“If I had left Ajmal’s delivery, it could have been a wide, but that is hindsight. You are in the moment and you just swing a bat on it. We are not out to tie games, and that is why it feels like a loss, to be honest,” he said.
The Ireland run-chase was built around Paul Stirling’s superb 103 from 107 balls.
The 22-year-old’s fifth one-day international century, and second against Pakistan, was a supremely mature and well-judged innings from a batsman more known for his power hitting.
Having won the toss and chosen to bat, Pakistan’s score of 266-5 in 47 overs was constructed on the foundation of a 188 stand between Asad Shafiq (84) and Mohammad Hafeez, who was undefeated on 122 off 113 balls 12 fours and two sixes.
Under the Duckworth-Lewis method, the score was revised to a target of 276 to take into account the multiple rain delays.
Pakistan batsman Asad believes Ireland will be full of confidence when the two sides meet again in the second and final one-day international at Clontarf on Sunday.
“They played very well, and we are expecting another tough match. It will be very good preparation for our Champions Trophy campaign (in England in June),” he said.
First One Day International, Dublin: Pakistan 266-5 (Mohammad Hafeez 122 not out, Asad Shafiq 84) v Ireland 275-5 (P R Stirling 103, K J O’Brien 84 not out). Ireland tied with Pakistan (D/L Method).