The Scottish midfielder scored twice last season when Burnley ended the young Gunners' Carling Cup campaign but admits that it is a different prospect playing the senior side at Turf Moor on Wednesday night.
McDonald said: "The match last season was probably the highlight of my career so far, it was a really special occasion.
"You can't look back at that though - this will be a different team.
"They are not sitting close to the top of the league for nothing, and they are a great footballing side.
"Guys like (Andrey) Arshavin, (Cesc) Fabregas and (William) Gallas are all top players and it's only once every so often that you get to play against these boys, so you just have to take your chance.
"We are underdogs every game we play home and away and that's a benefit for us - no one expects anything from us."