A 0-0 draw at home to Sporting CP on Wednesday saw Arsenal win their quarterfinal tie 1-0 on aggregate.
Martinelli enthused afterwards: “It feels amazing. We're really happy with this achievement - everyone is buzzing in the dressing room and we're really happy.
“We did well in the first leg of the quarter-finals and today I think we did quite well. Of course, we could have done better, but that's football and Sporting is a really good side as well, so they did well. We managed to not concede and we're through, so we're really happy and we can't wait to play against Atletico.
“I can't wait to get to the game, it's going to be another big one. Of course, we've played them this season, early in the season. Obviously, it's going to be a different game. We're looking forward to playing this game. It's going to be another battle.
“We're going to take what we did wrong last season to try to do right this season. We'll go for it and we can't wait to play them.”
The Brazil international significantly added: “I've been working hard for those moments, to help this team.
“This is my club, it's my family. I feel really good here and it means a lot to me. We want to win titles and I'm really happy with the way we've been doing things."