This is a very easy achievement to obtain. When entering MUT team, one of the quests in the tutorial is to complete a MUT Solo Challenge. It's rather easier than the rookie level difficulty. All you need to do is beat the computer in one game. The game is short with only two minutes quarters and the computer’s difficulty seems to be easier than the rookie setting. Here is a video on how to win solo challenges:
Credit to Kliquid T.V.