Manchester United pulled one of the shock results of the season when they beat Manchester City at the Etihad Stadium on Sunday afternoon.
Pep Guardiola's side went into the game having won 21 games in a row.
United, on the other hand, were coming off the back of three consecutive goalless draws.
But it didn't take the Red Devils long to break the deadlock against their fierce rivals.
Anthony Martial exploded into the box and he was felled by a clumsy challenge from Gabriel Jesus.
Bruno Fernandes would then make no mistake from the penalty spot.
United then doubled their lead in the second half after a wonderful solo effort from Luke Shaw.
There were no further goals and United held on to a memorable victory.
Harry Maguire has had his critics this season but he was a rock at the back for United on the day.
And one man that thought he had a good game was Eric Bailly.
The Ivorian defender did not feature against City but he decided to let Maguire know what he thought of his performance in typical fashion.
After Maguire posted about the win, Bailly bizarrely replied: "Top performance captain you have a big head!!!!"
Bailly's comment has gone viral, attracting over 3k retweets at the time of writing on a post by @utdreport.
In the nicest way possible, Bailly is just a bit different isn't he?!
To be fair to him, he's not wrong, but not sure he had to call out his teammate like that.
Bailly brings entertainment on a daily basis both on and off the pitch. That's exactly why he is such a fan-favourite.
Man United fans thought his comment was hilarious and you can view some of the reaction below:
Maguire praised Ole Gunnar Solskjaer and his staff following the win.
“We have brilliant coaches and a brilliant manager and brilliant analysts as well,” Harry said, per Man United's official website.
“Credit to them because they are the ones who sent us out in that formation and those tweaks when they have the ball. We knew they were going to keep the ball at times and the positions that they find themselves in, they have a lot of possession.
“We’ve seen that in recent games, so we had to be patient at times, but we had to make sure we kept getting up to the ball, kept getting contact, keep making tackles. I felt that we did that really well.
“For sure we can improve, we can do better in parts of the game. But it’s an important win, an important performance after a disappointing trip to London in midweek. Now we have to dust ourselves down and go again. We’ve got another big game on Thursday.”