The France striker has yet to start a league game this season and media reports before the match had suggested he could be loaned out in January to secure more playing time ahead of the 2018 World Cup in Russian Federation.
"Against this team [Arsenal] you have to play close to excellent, because they don't need too many actions to create problems but in both aspects, attacking and defending, we were intelligent and focused from beginning until the end", Pellegrino added.
"I felt that the Manchester United game played a bit of a part in the head of our defenders", Wenger said.
"First of all I think it's in the head of the players to respect the game and to play".
"It's hard when you start 35 yards away from goal".
But France striker Alexandre Lacazette could not claim the goal his endeavours deserved and it was left to his compatriot Giroud - a man, like Austin, not too well-versed in starting games this term - to avert a sixth Premier League loss of the season.
A poor clearance from Mertesacker conceded possession deep inside his own half and then slipped as he attempted to make up for his mistake, allowing Dusan Tadic the time and space to pick out Austin's run into the box where the striker finished from 12 yards out.
What followed, was an extended display of Arsenal's woes and concerns.
It was the flawless start for the home side and they should have been two up inside five minutes when Tadic and Austin again combined to open up the unconvincing Gunners back line.
Arsenal looked lively in the opening stages of the first half with Alexis Sanchez and Lacazette combing well, however they failed to test Forster. Arsenal's defence was picked apart by Charlie Austin and co.
But that will change after Thursday's final Group H game at home to BATE Borisov as, with Arsenal already assured of progressing as group winners, the competition will not be back on the calendar until February.