The Poland international believes there has never been a better time for Arsene Wenger's side to visit the defending champions with the Premier League leaders in outstanding form.
Arsenal outclassed Liverpool 2-0 last Saturday before winning 1-0 at Borussia Dortmund in the UEFA Champions League on Wednesday.
And Szczesny wants his side to finish a tough week with another big victory that would extend their advantage over David Moyes' side to 11 points.
"We are looking forward to Sunday now and we will be trying to make it a perfect week for us," Szczesny said.
"We have got two clean sheets and two results against quality opposition, one away from home at one of the toughest venues in Europe.
"It would be amazing to get nine points from these three games, when probably not a lot of people expected us to do.
"There is not a better time for us to go to Old Trafford. We are very confident and enjoying our football, so we are looking forward to it."
Arsenal head into Sunday's match on the back of a 15-match unbeaten streak on the road in competitive fixtures, with 14 of those ending in wins.
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