But Shakhtar remained dangerous and Darijo Srna's 22-yard drive flew just a foot wide and Boruc relied on his instincts to turn a Brandao header from just six yards over the bar.
Ireland's marking went missing as Mandzukic was given all the time in the world to head Darijo Srna's deflected right-wing cross into the net, with Irish keeper Shay Given struggling to get across his line.