The Spanish midfielder played the whole game as United won 1-0 at Benfica last night, thanks to rookie goalkeeper Mile Svilar carrying Marcus Rashford’s free-kick over his own goalline.
Jose Mourinho’s side have won all three of their group games and Herrera doesn’t think they’ll have any problems picking up the points needed to win the group.
"We have been solid, not only in the Champions League, but during the whole season," he said.
"We still have to improve of course, we have only played around 11/12 games, but we are really solid and in a good moment.
"We have nine points and are in the best position possible, so we are very happy. Now, we still have two games at home which are important for us.
“It's another clean sheet, we conceded almost no chances which is not easy when you come to Portugal. I have played here before and normally they create a lot of chances, but we didn't let them.
“Of course we want to keep improving and creating more chances but we are happy with three points and nine points in the group.
"We have to play against Benfica at home now and I think, with 12 points, we will be qualified which is very important.
"When you get results, you get more confidence and you play better. We hope we can continue to do that."
Svilar is the competition’s youngest goalkeeper at just 18 years and 52 days and he was consoled by fellow Belgian Romelu Lukaku at full-time.
Despite the error, Herrera appreciated the technique required from Rashford to create the situation and win United the match.
He added: “Marcus has a great shot, we know that.
"It was important in this match because he made it very difficult for the keeper. He had to run back to the goal, that's why the ball went inside [the line]. We trust in Marcus a lot because he has a fantastic shot."
Manchester United entertain Benfica at Old Trafford in the return fixture on October 31.
They return to league action this weekend as they travel to struggling Huddersfield.
