The 18-year-old's fine start to life at the Emirates Stadium continues as he claimed his second goal in two games on Tuesday night.
Martinelli scored a brilliant equaliser against Chelsea to put Arsenal level for the first time in the match, which eventually finished 2-2.
The Brazilian, who joined Arsenal from Sao Paulo side Ituano FC last summer for £6million, now has 10 goals in just 21 Gunners appearances.
Indeed, he is the first teenage goalscorer to reach double figures for the club since Nicolas Anelka in 1998-99, as well as three assists (Transfermarkt).
Bellerin was eager to point out how Martinelli's mentality, attitude and work ethic on the training ground, which people would not see, has been a key force behind his great form.
"To be fair there are not many [players Martinelli's age doing as well]," Bellerin told the Arsenal website. "A lot of people talk about his talent, but what people don’t see is that Gabi is a professional.
"He turns up early every day. He does all the stuff and everything anyone asks him to do. He is the first player to press and the last player to leave everything on the pitch. The goals are just a plus.
"He helps us in every single way and the thing that everyone needs to praise him for his attitude. That is what makes him a player. I think he is obviously really young in his career - so many things can happen - but if he keeps his head where it is right now, he is going to go really far for sure."
According to the Daily Mail, Martinelli's form has sparked interest from Real Madrid, who are believed to value Martinelli at around £50million.
In response, plans are reportedly in the pipeline for Arsenal to reward Martinelli with a pay rise from £10,000-per-week to around £30,000-per-week.
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