The side won their first major trophy of the season on Sunday as they beat Southampton 3-2 in the EFL Cup final at Wembley.
Man United are still in the last 16 of the Europa League and the FA Cup quarter-finals, but sit in sixth place in the Premier League, as a Champions League qualification remains the club’s top priority.
Speaking about Mourinho’s impact, Herrera claims the Portuguese boss is slowly restoring the fear factor which the United badge held under Sir Alex Ferguson.
“I think one of the things [Jose] Mourinho has brought to this club is he is a winner,” he said. “He shared that with the group, with the team and with the squad.
“At this moment, it’s not very easy to beat us. We have to respect every opponent but the badge sometimes wins the game. We keep going. It’s our second title of the season but it’s not enough for us.
“Already, we have to focus on Bournemouth as we have to be in the top four. We want to play in the Champions League next season.”
Herrera has done well to kickstart his career under Mourinho, using his arrival as a way to work his way back into the squad, and the Spaniard is now a vital member of the first-team.
Mourinho has a way of getting the best out of his players and he motivates them to improve their game by aiming for success, silverware and titles, with nothing less than victory as an option.
Hopes are the squad can maintain their impressive form as their on the right track this campaign and now sit within touching distance of the top four, with the chance to move ahead in the clash against Bournemouth on Sunday.