Pakistan skipper and star batsman Babar Azam absolved his bowlers of blame for the defeat.
Azam top-scored for the tourists with 57 in a total of 182-6 that also featured Saim Ayub’s 45, but the captain felt his side’s total had been below par.
“I think 190 would have been a par score,” he said.
“We lost in the fielding and batting. I don’t think we executed the plans. A few fielding lapses cost us.
“We attacked in the first six overs but didn’t finish well.”
Ireland needed 40 to win from the last four overs after Afridi dismissed George Dockrell for 24, but Balbirnie’s 55-ball innings, which included 10 fours and two sixes, and Campher’s late composure ensured the home side clinched a thrilling victory.
The teams meet again at the same Castle Avenue venue on Sunday and Tuesday.