Arsenal improved in the second half which wasn't hard given how poor they were in the first.
The man advantage eventually paid off five minutes later as Jack Wilshere spearheaded a trademark Arsenal passing move which led to Olivier Giroud adjusting his body well to score an overhead kick, adding to his collection of spectacular goals.
- Olivier Giroud has been directly involved in eight goals in his last eight starts in Europe for Arsenal (seven goals, one assist).
Such was Red Star's pressure that veteran keeper Petr Cech had to roll back the years to produce a fine save to keep it at 0-0.
Red Star was extremely organized in defense all game, but they also began threatening Arsenal's backline in the second half getting most of the chances. Walcott played a one-two with Wilshere who flicked the ball back to Walcott who headed it across goal.
But Arsenal needed Cech to keep the game goalless to that point, as the goalkeeper denied Nemanja Radonjic in both halves as well as a header from Nenad Krsticic - earning praise from goal scorer Giroud.
"Overall, the spirit we showed was remarkable, fighting together in a game that was very physical".
Progression from Group H now looks a certainty, with the Gunners sat five points clear in first place after three wins from as many matches.
Olivier Giroud strengthened his case in his battle for supremacy with Arsenal team-mate Alexandre Lacazette thanks to his sensational Europa League goal on Thursday. The Gunners continue Premier League action this weekend on Saturday against Everton.