The Scottish Premiership champions ended the match with nine men following red cards to Gustaf Lagerbielke and Odin Thiago Holm, with Feyenoord scoring goals via Calvin Stengs and Alireza Jahanbakaskh to secure the win at De Kuip. However, McGregor hailed the team's spirit when numerically inferior and believes Celtic can use that spirit to bounce back in the forthcoming matches.
"It was a difficult game," said McGregor. "I thought we started it really well, but they get the goal just before half time and that undoes a lot of the good work in the first half. And then to get two men sent off in quick succession takes the game away from us. But the boys hung in there. It could be easy to go down three, four, five, which is testament to the group.
"There's five games to go. Hopefully they'll be walking off thinking, 'we didn't give up, we didn't quit', and there's another game at Celtic Park to get them back. We have to take the lesson of playing with 11 men at this level. But the most positive thing is how we started the game and the fact that we didn't give up when we went down to nine men. We have five games to try and fix it."
Celtic manager Brendan Rodgers expressed his disappointment with the manner of Feyenoord’s opener, which came via a free-kick. “I feel for the players,” he said. “I think for the first 60 minutes it was a very even game against a team that’s doing well and scoring a lot of goals, and we matched them. I’m disappointed with the goal. We made a decision in the game to adjust the wall and it cost us, but we’ll take that, I don’t mind players making decisions in-game. Very disappointed with the two sendings off and nine men is obviously very difficult. If we get to the last game to play Feyenoord at home with everything to play for, we’ll be in with a fantastic chance."
Rodgers believes the red cards for Lagerbielke and Holm were down to inexperience. “First one you just have to shepherd it through to the goalkeeper, don’t get into the fight as it’s getting to Joe Hart,” added Rodgers. “It’s just inexperience. And Odin is a fantastic young player, he’ll learn from that, you can’t go to ground like that, particularly in Europe and he’ll learn from that."
In the other match in Group E, Lazio goalkeeper Ivan Provedel scored a dramatic equaliser five minutes into stoppage time to salvage a 1-1 draw against Atletico Madrid. The Italians are next up for Celtic in Glasgow on October 4.