Guimaraes completed a £75M switch from Newcastle United on August 8th and Arteta handed him a second half debut in last night's 1-1 friendly draw with Como at the Emirates Stadium.
The 28-year-old had been training with Newcastle in Spain prior to his move to the Gunners following his return from a post 2026 FIFA World Cup break.
He replaced Max Dowman at half-time against Cesc Fabregas' visitors and could now feature in the FA Community Shield against Manchester City on August 16th.
"He's only had three training sessions, but he looked good. He was really pushing to play some minutes," Arteta stated at full-time.
"He wanted to get his debut and the feeling of playing in front of our fans immediately. You sense it immediately. I believe there's a strong connection at play and that is going to make us better."
With Declan Rice, Martin Zubimendi and Mikel Merino just days back into their own preseason, Guimaraes could be drafted in for Arsenal's title defence opener, at home to Coventry City on August 21st.