Herrera has established himself as a regular member of Jose Mourinho's first team at Old Trafford, making 24 Premier League appearances this term and helping the club to EFL Cup glory.
However, the Spaniard insists that all of his and the team's good work will be forgotten if they fail to finish the season strongly in their bid to break into the top four and secure Champions League football.
"I am happy with my development and I am happy with my performances. But people remember the end of the season and now we are in the crucial moment. Nobody will remember this part of the season if I don't perform well at the end. I am happy but I am not finished yet," he told the club's official website.
"I like to demand a lot of myself because I feel I can give more, and more, and more to the team. I am happy and I think it is the right attitude. So far has been okay for me but I still have to show I can give more. The team will need me if I am on the pitch. I am a team player, I want to give everything for the manager and I don't look back. I just look forward.
"The next month and a half is the most important time of my career. That is the way I think and that is the way I see football. Also, when everyone is telling you you're having a great season, you're having a very good game, you're playing very well, I don't think it is good for yourself so I don't listen too much. I want to be focused on what is coming and that is very important. I want to play in the Champions League next season."
United will host Premier League leaders Chelsea on Sunday knowing that defeat could leave them nine points adrift of the top four.