Premiership cracks ’Well travel to Aberdeenshire as red hot favourites to win and book their place in the last 16 but Alexander is taking no liberties.
He said: “It’s a big thing in football that you respect all opponents. They are part-time, but I know from my own experience in the lower leagues that you put everything in and it means a lot.
"They will aim to make themselves look professional and we must overcome that.
“We know this is a cup that is fiercely-fought for. Every Premiership team has ambition in this.
"We have to have the right mentality going into this. I speak regularly about the mental preparation for the game and we have possibly let ourselves down a couple of times by taking the opposition lightly. We concentrate on ourselves.
“We will be the favourites and I won’t shy away from that. I think the Brora Rangers v Hearts game is the biggest warning.
"It’s the most recent one too. If you don’t approach things properly in professional sport, you can come off second-best.
"We don’t want that to happen.”
Motherwell players are back in action after a two-week break, determined to get the disappointing 4-1 league loss at Kilmarnock in the last outing out of their systems.
Alexander said: “The squad is good, people have come back into training. We have worked them really hard and that has continued this week. The squad is looking healthier than it was four weeks ago, we couldn’t even fill a bench. That isn’t the case now.
“It’s in a healthy state. We have a few senior players missing but at the moment we have a good healthy squad to pick from. But we will pick a team to win the game, not to prepare for anything else.
“I won’t think ‘let’s get minutes into people.’ We have to win this game, we can’t make any mistakes. The first thing we think of is the best team to win this game and we aren’t thinking ahead to any other game.”