A disciplined 0-0 draw against Sporting CP in the second leg ensured Arsenal progressed 1-0 on aggregate, following their narrow win in Lisbon last week. It marked a historic moment, as the club reached back-to-back semi-finals for the first time.
Martinelli praised the team's defensive resilience across both legs and highlighted the mood inside the dressing room after the final whistle.
"It feels amazing," he said. "We're really happy with this achievement. Everyone is buzzing and we're proud of what we've done."
Reflecting on the match, he added: "We did well in the first leg, and tonight we managed the game. Maybe we could have been better, but Sporting are a strong side. The important thing is we didn't concede and we're through."
The winger now has his sights firmly set on the next challenge against Atletico Madrid, who booked their place by eliminating Barcelona 3-2 on aggregate.
"I can't wait for it," Martinelli said. "It's going to be another big game, another battle. We've played them before, but this will be different. We're ready."
He also made it clear that last season's disappointment is driving the squad forward.
"We're going to take what we did wrong last season and try to put it right this time. We'll go for it."
Martinelli played a decisive role in the tie, creating the only goal in Lisbon for Kai Havertz. The Brazilian has now contributed eight goal involvements in this season's competition, underlining his growing influence on Europe's biggest stage.
"I've been working hard to help this team," he said. "This club is like family to me. We want to win titles, and we're on the right path."
Arsenal will travel to Madrid for the first leg at the Metropolitano Stadium on April 29, before hosting the return leg in north London on May 5, with a place in the final at stake.
