More: Watch De Gea's post-match interview with MUTV in the video player above. However, Mourinho thinks his team were hard done by, citing a challenge by Laurent Koscielny on Romelu Lukaku which only drew a yellow card.
Pogba sarcastically applauded Marriner as he headed for the tunnel and United boss Mourinho made it clear the France star wasn't happy with the decision or his global team-mate's part in it.
Discussing the Pogba red card, he said: "I don't know".
"The Neymar deal is special for me because it means journalists are not looking at the price any more. But I saved that ball and after that, I think he did a really good job".
Here, Press Association Sport takes a look at what we learned over the weekend.
Pogba is likely to feature on Tuesday night when United will seek to secure their place in the Champions League knockout stages against CSKA Moscow.
The England midfielder struck United's second after 11 minutes and a second-half third as Arsenal were pushing for an equaliser.
Until Pogba's dismissal, everything had looked flawless for United, for whom David De Gea was outstanding and was beaten only by Alexandre Lacazette just after the interval.
"At the beginning we needed to be patient with Brighton's style, " said manager Jurgen Klopp, whose side have scored 12 goals in their past three Premier League away games."We needed to get used to it".
"You have to dictate from the start and show strength in duels from the back", Wenger said. And the 24-year-old enjoyed a successful first season back at Old Trafford as United tasted success in the Community Shield, EFL Cup and the Europa League.
"We have produced an excellent performance but have conceded three goals and had at least 10 chances and were not efficient enough in the box, that is the reality".