Herrera gave Man United the lead at the Liberty Stadium but strikes from Ki Sung-yueng and Jonjo Shelvey sealed a 2-1 victory for the Swans.
The Spaniard’s goal was his fifth of the season, meaning he has already equalled his career-best total from last season at Athletic Bilbao.
Herrera is keen to keep up his goalscoring run, although he says the team must always come first.
Speaking about the run, Herrera said: “I haven’t really got a target for goals, I think we’re a very attacking side and I just want to help.
“I knew that scoring goals was one of the things I could improve on, but I don’t want to stop now, I want to keep working and helping the team.
“The most important thing is that we win, but of course, when I score I’m happy.”
Herrera’s form is impressive given that he was in and out of the team earlier in the campaign.