As European nights at Celtic Park go, this will go down as one of the strangest. Until the triple substitution on the hour mark, nobody in the grand old stadium could see a Celtic response coming.
They had just two touches in Besiktas' box in the first half, barely laying a glove on their visitors.
And when Johnstone's poor kick out was followed by Jordan Lotomba's rash challenge on Ernest Poku and a Besiktas penalty, the writing was on the wall for a side which looked utterly bereft of confidence.
However, Osmand and Duran completely transformed the energy of the Celtic team. They inspired their team-mates - and supporters - with their energy and willingness to run with the ball and play positively.
While Kasper Hogh, now 15 games without a goal, appeared hesistant, Osmand showed incisiveness with his first touch to surge forward and lash in.
Duran, now on 13 goals for the season, also demonstrated his usual sharpness and composure amidst the bedlam of a revitalised Celtic Park, which had plenty of empty seats amid ongoing fan unrest.
O'Neill has admitted he still is unsure of his best XI, but the 74-year-old will now surely have to include Osmand and Duran whenever possible.
As good as the victory feels, those two performances will not mask everything about Celtic's recent problems. But it could be the catalyst to re-inject some desperately needed confidence.