Gabriel Martinelli struck a hat-trick as Arsenal won this third round tie 4-1 at Fratton Park.
“That's what we need, our top players to make the difference, and he certainly did that today,” Arteta said of Martinelli.
“It's always tough to go into these places, especially in the manner that we started the game, conceding the early goal, but we managed to turn things around, so I'm very happy.
“(Making changes) is always tricky. You lack that cohesion; certain players as well haven't played that many minutes, but a lot of positives to take from the game, apart from the win.
“Marli (Salmon) making his debut in the FA Cup, Kai coming back as well, Gabi scoring twice in a different manner. That's what we need, that they start to take that rhythm, Noni as well, starting and influencing the game.
Arteta added: “We need everybody to be at it,” he added. “We have so many games coming up in different competitions, so we need to be at it.
“I think we are very privileged to be where we are, and the games that we have to play, which means that we are in every competition.”