The Brazilian was given his marching orders just after the hour mark after picking up his second yellow card in the space of four minutes.
The Gunners hung on to claim a point, but Arteta afterwards bemoaned his side going down to 10 men once again – having also had Granit Xhaka sent off during the 1-0 defeat to Burnley on Sunday.
“The fact that we played 35 minutes with 10 men, we have to take the point,” said Arteta.
“We showed some resilience and character to hang in there for so long against a really dangerous team.
“But at the same time we are disappointed because we came back after conceding the goal, we showed how much we wanted it, we created some situations and after half-time we corrected a few things.
“We came back really strong in the game, we scored a good goal, and when we had the best moment again we shot ourselves in the foot.
“That obviously makes it a little bit harder.”
Gabriel’s red card was Arsenal’s second in four days, while they also had one last month in the draw at Leeds when Nicolas Pepe was sent off.
Indeed, since Arteta’s first Premier League game in charge on Boxing Day 2019, Arsenal have been shown seven red cards – four more than any other top-flight side in the same period.
And Arteta said: “It is very difficult to compete in this League when you play such a long period with 10 men.
“It makes it more difficult and complicated, but I think that the boys stand up for it and they showed again a lot of character and resilience.
“They never gave up and after 1-0 I was worried, because after this moment you can start to see players hiding. But they did completely the opposite.”