After Ayase Ueda had given Feyenoord the lead, goals from Yang Hyun-jun and Ryo Hetet put Celtic ahead, before Benjamin Nygren’s late goal ensured an historic victory.
It is Celtic’s first win in the Netherlands since 2001, when O’Neill was first in charge and knocked Ajax out of Champions League qualifying.
“We played really well,” he said. “There were times when we were dominating, controlling the ball and showing a lot of confidence, which was good to see.
“Being down a goal, we could have fallen apart. But we showed character and resilience and then when we got the equaliser, the team gained confidence.
“I told the players ‘You’ve got to play tonight’. We took that chance.”
Celtic play Roma at home and Utrecht in their remaining three league-stage fixtures, either side of a trip to Bologna. They are at 21st place in the table of 36 teams with seven points.
“Looking at last season, you’re looking for 10 or 11 points to qualify,” O’Neill said. “It won’t be easy, but Celtic have two home games to play and there is confidence in the team now.”
Columbus Crew head coach Wilfred Nancy appears close to being appointed as Rodgers’ permanent successor and O’Neill feels the Celtics are in a good position to have the new man in charge, whoever it is.
“They’ve got some guys who are big winners,” O’Neill said. “I’m sure he’ll build on some of those players and then it’s about improving some of the other players.
“Rebuilding trust is a big thing and that will continue after that.
“It’s great to win away from home – it’s not easy away from home in Europe. It gives them confidence that they can come and compete.”
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