Belfast: Ed Joyce's controversial run out overshadowed Ireland's 79-run defeat as Afghanistan moved 2-1 up with one game to play in the one-day series.
As Ireland chased 229-7 at Stormont, Joyce was run out for 12 by Mirwais Ashraf after thinking that he had struck a four.
Joyce's frustration was clear as he made a two-fingered gesture as he walked to the pavilion.
As Irish wickets tumbled, they were dismissed for 150 in the 42nd over.
Afghanistan captain Asghar Stanikzai was asked by the umpire to withdraw his side's appeal but when the tourists refused Joyce was given out.
Ireland captain William Porterfield was batting along with Joyce during the game's big talking point and said the Sussex batsman was emphatic his shot had gone for four.
"Ed said that he saw him [the fielder] crossing the rope and flicking it back," said Porterfield.
"But the fielder has come in and said he didn't. I don't know what footage is out there but the umpires said they have to go on the fielder's word."
Joyce's century helped Ireland win at Stormont Thursday and the home side will have to win Tuesday's final game to level the series 2-2 after the first game was abandoned.
After Joyce's controversial exit, Porterfield was also run out to put the home side on 36-2 and the departures of Sean Terry and Stuart Poynter left them on 67-4.
Kevin O'Brien and Paul Stirling put on 63 for the fifth wicket but they both quickly dismissed as Ireland slumped to 134-6.
As teenage spinner Rashid Khan finished with impressive bowling figures of 4-21, the Irish were unable to sum up any late resistance as the visitors quickly wrapped up a 79-run victory.
Earlier, Afghanistan had been in a degree of trouble at 90-5 as Andy McBrine claimed two wickets but after Rahmat Shah's 48 steadied the innings, Rashid Khan's unbeaten 60 and Mohammad Nabi's 50 saw the visitors post a competitive total on the difficult batting track.
Ireland's chances were not helped by a couple of dropped catches that Porterfield admitted had been important.
Brief scores
Afghanistan - 229 for 7 (Arman 60, Nabi 50, McBrine 2-29)
Ireland - 150 (Kevin O'Brien 34, Arman 4-21)
Result - Afghanistan won by 79 runs