The Gunners were cruising toward a dominant victory when Mesut Ozil put them 4-0 up in the 74th minute after two goals from Pierre-Emerick Aubameyang and one from Danny Welbeck already had them comfortably in front at the Emirates on Thursday.
"Little by little, we are conceding a few chances to the opposition, the same like in Newcastle".More news: Local clinics say flu shots are hard to get this season
The night didn't end perfectly for the gunners as Vorskla scored two late goals to deny the Gunners a clean sheet.
The visitors bagged a consolation goal two minutes later as Lichtsteiner went from hero to zero after giving the ball away on the edge of the box, allowing Volodymyr Chesnakov to pounce and fire past Leno.
Speaking to BT Sport as quoted by the Daily Star, Emery said: "Each match we play, I am responsible for the group and for Torreira also, today I think it is better [for Lucas] to leave the match". We need players and need to give minutes to players.
Emery remains hopeful Torreira will feature against Everton in the league on Sunday after the Uruguayan midfielder picked up a knock on his knee in the second half. I want to continue to be competitive in each match. He didn't say the league is Petr's competition and the Europa League is mine.More news: Pedro injury 'probably' not serious - Chelsea manager Maurizio Sarri
"Each minute he is playing, he is doing very well", he added.
"I came to the club to play every game", Leno told the London Evening Standard.
"For him, it takes minutes for the game and confidence for continuing also because he will be continuing to play matches in the next week".More news: The Victory Fridges Were Opened After The Browns Finally Won A Game