Northern Ireland manager Michael O'Neill admitted he was going to substitute Kyle Lafferty before the striker salvaged a vital point with a late equaliser in a 1-1 draw against Hungary.
A dramatic final 20 minutes in Belfast saw Hungary take the lead, courtesy of an error by Northern Ireland goalkeeper Michael McGovern that allowed Richard Guzmics the easiest of tap-ins, before Chris Baird was sent off for the home side.
But Lafferty pounced on a rebounded shot deep into injury time to score his second goal in two games, and secure a win that leaves Northern Ireland needing just two points from their final two games against Greece and the Faroe Islands to qualify for Euro 2016.
O'Neill said: "We were going to take Kyle off at 0-0 as he was shattered. He's had a lack of football and training coming into these two games.
"He trained for a week on the back of a knee injury, and by his own admission his performances haven't been at the level he's capable of, but he has given us two goals and as soon as they scored we had to keep him on the pitch.
"We had to go to 3-4-2 and it was just a case of hanging in there."
O'Neill acknowledged that a second Hungary goal could have been deadly for his side, who hold the edge over their visitors in a head-to-head contest if they end up level on points in Group F.
"With a 1-0 defeat, our head-to-head record is better, but 2-0 would have changed the whole complexion of the group, so we had to chase with an air of caution," he said.
"Ultimately it paid off."
O'Neill questioned the red card to Chris Baird, who was shown two yellow cards in quick succession by referee Cuneyt Cakir but play only paused following the second of his two challenges.
"He [Baird] was booked for the first challenge but the referee let the play go, and then booked him for the second challenge," the 46-year-old manager said.
"Chris has no dispute over the second booking but he didn't know he had been booked for the first."
O'Neill added: "I've never seen that before. It's unusual to say the least."
