McGovern, who was released by Hamilton Academical at the end of last season, produced a string of brilliant saves to keep the Green and White Army in the game and the tournament.
Germany dominated the Group C match at the Parc des Princes in Paris, having 28 shots and 79% of the possession.
But O'Neill's men held on and claimed their place in the knockout stages – courtesy of Turkey's win over Czech Republic later that evening in Group D.
And the Irish coach has since hailed McGovern as one of the country's best-ever shot-stoppers.
"It was a phenomenal performance, and up there with the great goalkeeping performances we've had in the past from the likes of Pat Jennings and Tommy Wright," said the 46-year-old.
"He's an exceptional goalkeeper. The types of saves he made showed not only his bravery but his speed in closing people down.
"He didn't put a foot wrong all night."
Germany exerted their dominance early on but McGovern was determined to keep the scores level, saving efforts from Bayern Munich duo Thomas Muller and Mario Gotze, and Arsenal midfielder Mesut Ozil.
The world champions eventually found a way through, with Muller setting up Mario Gomez to slot home.
Despite the setback, McGovern made sure that the scoreline stayed low finishing the match with eight saves to his name.
The Northern Irish shot-stopper even received a nod from the German team, after they posted on their official Twitter feed that "there was only one man taking [German goalkeeper] Manuel Neuer's shirt home. Well played, Michael McGovern!"
The narrow defeat ensured Northern Ireland progressed to the next round, finishing as one of the best third-placed teams and could face either Wales or hosts France.
"It's not really sunk in – I'm delighted to have played so well but also delighted for the team to have qualified last-16." said 31-year-old McGovern.
"Before the tournament began we said we wanted to get out of the group and that we weren't here to just make up the numbers.
"To achieve that goal is very satisfying and we want even more of it now."
Source: Sportsbeat
