The goal was his 100th career strike.
"The three points is the main thing. We had a very tough game against Southampton, we got a great point at PSG in the week and we've been tested this week with a coupe of away games," he told arsenal.com.
"Hull wasn't going to be easy - they've had a very good start and I think they'll take a lot of points against teams here. Sometimes people say it's a lot easier when teams go down to 10 men but it is very difficult to be honest, because you need to break them down. Giving away the penalty was a bit scary but the guys fought on well and Alexis got his deserved goal."