For much of the game, Northern Ireland were off their game, sloppy in possession and unable to create any clear sights of goal, but despite a draining heat they refused to lie down and got their rewards.

"We've a lot of players here who are possibly not coming off the best they've had in their club careers, not played a lot, some are looking for a club," O'Neill said.

"They're here to be part of a squad, to try and get results for qualification so they deserve an enormous amount of credit. I'm proud to be associated with them."

It was O'Neill's substitutes who changed the game. Washington, now a free agent after leaving Sheffield United, replaced Liam Boyce at half-time, while Magennis came on to add a physical threat and Jordan Jones stretched Estonia on the wing.

"We had to take risks," O'Neill said of his attack-minded changes.

"We knew Vassiljev could hurt us, he hit the bar as well, we knew that there was a risk of going 2-0 down as opposed to 1-1 but that was a risk we were prepared to take.

"When the game's open like that and the players are tired and it's this stage of the season, then anything can happen and I thought they deserved enormous credit for how they played in the second half."

Defeat would have dealt a huge blow to Northern Ireland's Euro 2020 qualifying hopes given home and away games against Holland and Germany are to come later in the year, but they now go to Belarus on Tuesday looking to make it 12 points out of 12 in Group C.

Though the hot and humid conditions in Tallinn will no doubt have drained the legs of his players, many of whom were playing for the first time in a month, victory will have done wonders for their mindset.

"What we have is three points from a game that we thought we were going to lose," O'Neill said.

"It was possibly very damaging to our hopes and we've got a victory out of it, that helps with fatigue and physical tiredness.

"The mental tiredness as much as the physical is what you have to combat and when you win like that you're obviously ready for the next one and that will be a big factor for us on Tuesday."

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