Saka missed a first-half penalty but scored the opening goal in his side's 2-1 victory in the Bernabeu to seal a 5-1 aggregate win for the English club.
The return of Saka is a huge boost for Arteta, who has been short of firepower in recent weeks, with Kai Havertz and Gabriel Jesus out of action with long-term injuries.
Saka is set to be sidelined for "many weeks" in the words of Gunners' boss Arteta with fears the England international could be out until March due to a hamstring injury suffered in last weekend's 5-1 victory at Crystal Palace.
Asked at a press conference about the 23-year-old England international's condition, Arteta said: "It is not looking good. He will be out for many weeks."
Should Saka, Arsenal's player of the season so far, be out for a significant time with a hamstring injury, an in-form Jesus will certainly be needed.
Bukayo Saka's double fired Arsenal a step closer to the Champions League last 16 as the England forward inspired a 3-0 win against Monaco on Wednesday.
Bukayo Saka became the youngest Arsenal player to score 50 Premier League goals when he returned from a hamstring injury in Sunday's 2-2 draw with Liverpool, but the winger was disappointed to drop two points after being on the verge of a crucial win.
England winger Bukayo Saka has returned to Arsenal for further assessment of a leg injury and will miss Sunday’s Nations League match in Finland, the England team said on Saturday.
Kai Havertz and Bukayo Saka inspired Arsenal's 2-0 success against Paris Saint-Germain on Tuesday as the Gunners secured their first win in the Champions League this season.
"Dreams don't come true overnight," Saka said in Arsenal's announcement on their social media channels
Saka, who came through Arsenal's youth ranks, has been in top form for the London club this season with 12 goals and 10 assists in the Premier League as they lead the points table
The winger created England's opener for Harry Kane in the comfortable 2-0 victory over Ukraine in Euro 2024 qualifying Group C at Wembley on Sunday, then scored an absolute beauty himself to seal the man-of-the-match award
