Louis van Gaal cursed a "stupid" error from Anthony Martial after Manchester United drew 1-1 at CSKA Moscow on Wednesday.
Martial scored a fine diving header to grab a point for United at the Khimki Arena, but the French striker was to blame for gifting the Russians the lead.
Martial raised his right arm going into a challenge with Mario Fernandes in the 15th minute and the ball struck it, leaving the referee with no option but to point to the spot.
David de Gea saved Roman Eremenko's penalty but Seydou Doumbia scored the rebound to put CSKA ahead.
Martial's second-half header saved United's blushes but their manager was disappointed with his star teenager for the error that led to the hosts' goal.
Van Gaal said: "They had the present of an Anthony Martial penalty.
"Martial is a human being, he reacts and it is a stupid reaction, but sometimes these things happen.
"He said it is the first time it happens to him; if it always happens with me it's a pity."
Had it not been for a fantastic save from De Gea to deny Ahmed Musa, United would have been 2-0 down at the break.
The visitors put in a shoddy first-half performance, but improved after the break - thanks partly to the introduction of Marouane Fellaini - and deserved to take a point home from their trek east.
Wolfsburg beat PSV on Wednesday, which means United are second in Group B at the halfway point of the group stages.
Van Gaal said: "We now have two home matches and you can say we are very strong at home and I hope we can win these games so we are nearly qualified or qualified, but we also have a game away to Wolfsburg.
"We are on schedule (to qualify) after the PSV Eindhoven defeat, which was a very strange defeat for us."
In a break with custom, United stayed in Moscow after the game. They will fly back on Thursday afternoon and then begin preparations for the Manchester derby, which takes place at Old Trafford on Sunday.
United will leapfrog City to the top of the table if they win and Arsenal drop points against Everton in their game on Saturday.
Why are you making commenting on The Herald only available to subscribers?
It should have been a safe space for informed debate, somewhere for readers to discuss issues around the biggest stories of the day, but all too often the below the line comments on most websites have become bogged down by off-topic discussions and abuse.
heraldscotland.com is tackling this problem by allowing only subscribers to comment.
We are doing this to improve the experience for our loyal readers and we believe it will reduce the ability of trolls and troublemakers, who occasionally find their way onto our site, to abuse our journalists and readers. We also hope it will help the comments section fulfil its promise as a part of Scotland's conversation with itself.
We are lucky at The Herald. We are read by an informed, educated readership who can add their knowledge and insights to our stories.
That is invaluable.
We are making the subscriber-only change to support our valued readers, who tell us they don't want the site cluttered up with irrelevant comments, untruths and abuse.
In the past, the journalist’s job was to collect and distribute information to the audience. Technology means that readers can shape a discussion. We look forward to hearing from you on heraldscotland.com
Comments & Moderation
Readers’ comments: You are personally liable for the content of any comments you upload to this website, so please act responsibly. We do not pre-moderate or monitor readers’ comments appearing on our websites, but we do post-moderate in response to complaints we receive or otherwise when a potential problem comes to our attention. You can make a complaint by using the ‘report this post’ link . We may then apply our discretion under the user terms to amend or delete comments.
Post moderation is undertaken full-time 9am-6pm on weekdays, and on a part-time basis outwith those hours.
Read the rules here