The Portuguese international played the full 90 minutes against Vitor Guimaraes in the 4-0 win on Thursday, and even got on the score sheet, heading in the second goal from an Alex Telles corner, close to the hour mark.
Danilo has been repeatedly linked with the Gunners in the Portuguese press over the past two years, and it seems the club are continuing to keep tabs on the 26 year old.
The defensive midfielder is no doubt having one of his best seasons for Porto, having made 22 appearances already, scoring four goals and providing three assists. He has helped guide his side to an unbeaten start to the league season, with the team’s only defeats coming in the Champions League group stage games against Besiktas and RB Leipzig.
The Portuguese star has a €60million (£53m) release clause, and considering his importance to Porto, the player will likely not be sold for below that sum.