Mark O'Hara, Christopher Long and Mugabi gave Motherwell a healthy win away from home against a stronger opponent in Aberdeen who have been in good form given their previous performances.
“Today [Sunday] was a brilliant result for us,” Mugabi said as per Football256.
“It was a nice game to get my first goal for the club and start climbing higher on the table.”
He has played 17 games and has scored just once.
On his part, Mugabi’s manager Stephen Robinson said the win has helped them turn a corner especially after previous criticisms that were directed to them for poor results.
Motherwell moved up to eighth position after their second straight league victory.
“We took criticism when we weren't winning games and we were still playing well,” Robinson told BBC Sport.
“We always believed in what we were doing here. We've shown our quality. I believe we have turned a corner.
“I've got a group of boys who give me absolutely everything. When you have some games that don't go your way - people question that. It's never been a question for me.
“The difference between some of the other games this season was that we were clinical. We've played some really good stuff but we took our chances when they came.
“We've won four out of five now but we'll just keep quietly going about our business.”
On his part, Aberdeen manager Derek McInnes conceded their opponents were far better than them.
“Motherwell were by far the better side,” said McInnes.
“I thought they looked the hungrier team. I thought they looked like a team ready to win points and we looked like a team just out to play a game of football. We were well beaten.”
Mugabi and his teammates will now focus on their next match against Hapoel Beer Sheva of Israel in the third round of the Europa League qualification. Aberdeen will be up against Sporting CP of Portugal.