The return of German playmaker Mesut Ozil, who laid on a handsome backheeled assist for Lacazette's goal, also helped Arsenal fans to forget the absence of Sanchez, who was left out of the squad for a second straight game. "I think it is so close, so close, so close that if it doesn't happen it's not going to happen".
"I'm not the guy with the mathematics, with the numbers", Guardiola told a news conference on Friday.
"I expect it to happen maybe, but I can not announce it".
Meanwhile, United are close to reaching an agreement with Mourinho over a new contract to extend his Old Trafford stay beyond 2019.
Mkhitaryan said a tearful farewell to his team-mates and club staff on Friday lunchtime as the final obstacle to United signing Sanchez was removed.
"Clearly everyone knows that we are there and especially when the Arsenal manager speaks so clearly like he did, there is no point in trying to hide or deny", Mourinho said.
It was a third successive league victory for Mourinho's men, and they kept a clean sheet for a fifth consecutive match in all competitions - they are yet to concede a goal in 2018.
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Mourinho also said his attack could do with that extra "competition" for places.
Arsenal manager Arsene Wenger expressed confidence over the talent in the club without Alexis Sanchez.
"We know the way they play, they are better than anyone playing that way, we had to adapt to be successful, we adapted well from the defensive point of view".
In the first game the German giants thumped the Gunners 5-1 before doing the same in the second match to record a 10-2 aggregate scoreline.
"I like the player".
"In this moment, there is no competition for places", the United boss said.More news: Goa tourist taxi strike heads into Day 3
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