Manchester United manager Louis van Gaal acknowledged fans' unhappiness over his tactics, but insisted they would not be upset after Tuesday's Champions League win over CSKA Moscow.
The Dutchman's decision to replace Anthony Martial with Marouane Fellaini at 0-0 drew jeers at Old Trafford.
Wayne Rooney later scored the only goal of the game in the 79th minute.
"I'm not deaf. That's the opinion of the fans but afterwards they shall not be disappointed," said Van Gaal.
Rooney's goal - his 237th for United, moving him joint-second in the club's all-time goalscorers' list, alongside Denis Law - was the team's first in 404 minutes, a run including goalless draws against Manchester City, Middlesbrough and Crystal Palace.
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United legend Paul Scholes has blamed the team's lack of creativity on Van Gaal's tactics, while the 64-year-old's tendency to deploy Martial - who has scored one goal in his past nine games - on the left and persist with England captain Rooney as his main striker has drawn criticism.
France international Martial played up front alongside Rooney against CSKA but his substitution in the 66th minute drew an angry response from the crowd, who chanted the teenager's name and demanded more attacking intent from their side.
"I'm very happy because I put Rooney again in the striker's position and he scored," said Van Gaal.
The keyboard boos
It was not just inside Old Trafford where frustration over 19-year-old Martial's substitution was felt, as social media activity peaked too.
In 15 minutes from 21:05 GMT the term "Martial" was tweeted more than 13,000 times, with 2,600 tweets sent in the minute he was taken off.
Tweets were seen as far afield as Lima, Peru, while in Nairobi, United fan Iain Felipe wrote: "I have never questioned LVG's decisions up until now."
A particular meme often shared in the David Moyes era was also again sent around social media, with Van Gaal's face replacing the Scot's.
Was Van Gaal right to substitute Martial?
BBC Radio 5 live pundit Pat Nevin described the decision as "a shocker". "He was the last player I expected to be taken off," added the former Chelsea player.
In his 66 minutes, Martial touched the ball 30 times and played 14 passes, completing 57%. At the same stage in the game, Rooney had touched the ball 34 times, making 82% of his passes.
"Wayne Rooney was there to get that chance that was unmissable," added Nevin. "So once again, Wayne Rooney - without playing brilliantly - wins the game for United."