'We are a family': Martinelli says team spirit is high as Arsenal go top
Martinelli put Mikel Arteta's side ahead with a cool finish after just 58 seconds at the Emirates Stadium on Sunday.
Bukayo Saka's brace, including a late penalty winner, gave Arsenal their eighth victory from nine league games as they moved one point clear of second-placed Manchester City.
After blowing the chance to qualify for the Champions League with a late collapse last season, Arsenal were written off as also-rans ahead of this term.
But they have emerged as strong title candidates and Brazilian forward Martinelli believes it is the unity forged by Arteta and his players that has made the difference.
"We are running for each other all of the time. We are a family and everyone is on their toes," Martinelli said.
"It doesn't matter what your age is, it is the heart and how much you want to achieve in football and life.
"We need to go game by game, trying to win all of them, this needs to be our mentality."
Arsenal haven't won the title since 2004 and endured a prolonged spell in the doldrums during the final days of Arsene Wenger's reign and under his successor Unai Emery.
Arteta, who has already won the FA Cup as Arsenal boss, has impressively rebuilt the Gunners and Martinelli said the win over Liverpool showed they are a force to be reckoned with.
"It means a lot for us," he said. "I think we deserved the win and we need to keep going because the season is long. We want to achieve good things this season."