The January signing insists Celtic aren't in Italy to be 'tourists.'
The January signing was influential during the Bhoys' first-leg tie with the Serie A outfit and knows Celtic face an even tougher test at the San Siro at 6pm (GMT) today.
A 3-3 draw at Celtic Park handed Roberto Mancini's men the advantage on away goals but Mackay-Steven insists the Scottish champions are going to Italy with high hopes.
And, to make any kind of result possible, the 22-year-old knows Celtic must cut out the individual errors and not allow Inter any space on the ball.
So far this European campaign, Celtic have been guilty of both of the above and their goals conceded column stands as proof the Hoops must tighten up at the back.
“We’re not here to be tourists. We’re here to do a job and that is to get a result," he said.
“If we can cut out errors and not give them too much space we can create chances ourselves so there’s no reason why we can’t go into the game thinking we can win it.”
Beyond the Inter clash, Celtic face another huge game in the Scottish Premiership this Sunday afternoon, when they host second-placed Aberdeen.
For now, however, Ronny Deila's men will take to the San Siro - and, if the second leg is anything like the first, we'll be in for plenty of drama.