Arsenal confirmed the signing today of Brazilian star Marquinhos, but probably not the one you're thinking of...The Gunners' official Twitter account posted a welcome message to their first summer signing, with the caption "Welcome, Marquinhos."Naturally, this excited the club's fans into thinking they had pulled off a serious coup by signing the 28-year-old PSG captain who is considered one of the best central defenders in world football.Arsenal@ArsenalWelcome, Marquinhos 377606169Welcome, Marquinhos 🙌However, they were left disappointed when they discovered that the north London outfit had actually signed a19-year-old winger from Sao Paulo.Nevertheless, it appears as though Mikel Arteta's side have an exciting prospect on their hands, with the 19-year-old considered a talented left-footed winger who is capable of playing on either flank as well as behind the striker.Marquinhos made 33 appearances for the Brazilian giants last season and has played for his national side at U17 level, with the Gunners announcing the teenager has signed a "long-term contract" at the Emirates Stadium.Still, Arsenal fans couldn't hide the fact that they felt a little bit duped by the original post, and they took to Twitter to make their feelings known:claudio✰@ClaudioS2007@Arsenal saw the noti and thought marquinhos from psg @Arsenal saw the noti and thought marquinhos from psg 💀💀cody🇮🇪 Ħ@liqxzbb@Arsenal Bro I got a noti and thought we singed the CB@Arsenal Bro I got a noti and thought we singed the CB😭finers7@fpipez7@Arsenal Baited@Arsenal Baited🗿@AFCLiamm@Arsenal Wrong Marquinhos2@Arsenal Wrong MarquinhosRyan 🇳🇱@ibroxfpn@Arsenal Thought this was the good one@Arsenal Thought this was the good oneSam_Potts@SamPott49213893@Arsenal Notification had me gassed @Arsenal Notification had me gassed 💀؟@RV19_LUHG@Arsenal Nah this had me in a Cardiac arrest for 10 seconds@Arsenal Nah this had me in a Cardiac arrest for 10 secondsJaden@Jiddle03@Arsenal I thought it was psg marq wtf@Arsenal I thought it was psg marq wtfBrazil legend Edu excited by Arsenal's first signing of the summerArteta's side are in desperate need of attacking reinforcements during this window, with their lack of firepower costing them in numerous encounters towards the end of last season. Arsenal's technical director Edu said of the teenager via the club's official website:“We’re delighted to have completed the transfer with Sao Paulo, as Marquinhos was a player we had been watching for a while. At 19, he is still very young, so he is a player for the future. We look forward to Marquinhos now joining us for pre-season, making his new home, and continuing to grow and develop with us.”Arsenal will also be keen to sign a centre-forward this summer following the departures of Pierre-Emerick Aubameyang and Alexandre Lacazette, with Eddie Nketiah's future also appearing uncertain.After a campaign without continental football, Arteta's side will compete in the Europa League next season, having been pipped to the last Champions League spot by their great rivals Tottenham.Topskills Sports UK@topskillssports Nketiah ended the season strongly with five goals in his last seven Premier League games as the Gunners fell short in their bid to secure Champions League qualification. #AFC Mikel Arteta wants to convince the 23-year-old his future lies at the Emirates Stadium.587🚨 Nketiah ended the season strongly with five goals in his last seven Premier League games as the Gunners fell short in their bid to secure Champions League qualification. 🔴 #AFC Mikel Arteta wants to convince the 23-year-old his future lies at the Emirates Stadium. https://t.co/CUyXU0O5fM