Jesus was forced to undergo knee surgery following a tear in his meniscus during Brazil's clash against Cameroon late last year. At the time, the forward managed to continue playing for another quarter of an hour before he eventually had to be withdrawn by boss Tite.
At the time, it seemed like an inoccuous knock that would barely hinder Jesus' World Cup campaign, let alone rule him out of club action for more than three months. But soon after the injury had been sustained, Jesus discovered via national team doctors it was something far more serious.
As part of a docu-series focusing on Jesus' recovery and rehabilition process, Martinelli has discussed the moment he found out his Arsenal and Brazil colleague was facing a lengthy spell on the sidelines.
"At half-time, he said he was feeling something in his knee, but I didn't think it was that bad," the 21-year-old explained to the documentary. "I think it was the day after the game, he went to do the scan and he was in the canteen where we were about to have lunch.
"He said there was something in his meniscus and he needed to have surgery."
Martinelli himself suffered a similar kind of injury that saw him miss out on a lot of action around the opening exchanges of Arteta's reign.
"When you have this type of injury you get sad, you know? You could see in his face he was sad but at the same time you could see that energy that he has, that hunger that he has and he was telling everyone he was going to come back stronger and that's what he tried to do."
Jesus also discussed his initial response to the news, adding: "I was sad, I was crying a lot in the day but as soon as day two came along, I started to laugh and smile because it was in the past."
Nearly a full four months after his injury, Jesus has since returned to the Arsenal first-team and featured in the last three Gunners fixtures, though the four-time Premier League winner is yet to complete a full 90 minutes since his comeback.
He has shown very little sign of rust despite his prolonged absence, with Jesus already displaying some deft touches and dazzling dribbling, though a goal has evaded him so far.