Martinelli was signed by Arsenal last summer for £6.3m from Brazilian club Ituano.
Little was known about Martinelli bar the fact a host of European clubs were chasing him.
He previously had trials at Manchester United and Barcelona who both rejected the youngster.
Now the Brazilian is emerging as a top talent, exemplified most recently by his breakaway equaliser against Chelsea on Tuesday night.
Martinelli's 10 goals across all competitions make him the first teenager to reach double figures in a season for Arsenal since Nicholas Anelka.
According to the Daily Mail, The 18-year-old's rise has caught the eye of Real Madrid and Arsenal are keen to renew his contract.
It's reported that Arsenal will look to raise Martinelli's wages from £10,000 per-week to around £30,000 per-week.
Martinelli, who has featured for Brazil's U23 side, holds an Italian passport which means he could elect to play for them in the future.
However, it seems unlikely given Brazil's number nine role could be very much up for grabs in the coming years.
Arsenal are already expanding and intensifying their Brazilian scouting network to find the next Martinelli.
"The way the market is going, the European clubs are looking not so much for established stars, they're looking for the likes of Martinelli," South American football expert Vickery told Sky Sports News.
"The Arsenal scouting unit are looking for players in Brazil who are by no means household names in their own home at the moment."
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