A tight affair was decided midway through the second-half when Philogene, a £5m arrival from Aston Villa late on in the summer window, went solo and scored a fine goal to break the deadlock.
It made amends for a moment that the winger would prefer to forget just before the break when he delayed in front of goal after being sent clear by Jean-Michael Seri and Preston’s defence managed to clear.
Rosenior admitted that the miss affected the 21-year-old at half-time.
He was feeling better at the final whistle as City won for the first time in six matches at the MKM Stadium in front of a big 24,000-plus crowd.
Rosenior, whose side boosted their top-six prospects by backing up their midweek win at Birmingham City with another important three points, said: “That is the learning of a young player.
"He was so disappointed in the changing room afterwards and we got around him as a group and said: ‘That next one will go in’.
"The next one did not go in because the goalkeeper made a great save. So he saved his best until last and it was an unbelievable individual goal and that’s what he is capable of.
"All in all, it was a really pleasing day.
"It’s a big three points and we showed different sides to our game today. We have been working on being more resilient, organised and harder to beat.
"All of those things came into play in the last ten minutes. I think for 80 minutes, we completely controlled and dominated the game.
"With more ruthlessness in the final third, we don’t have to show that side of the game.
"That is more like us from last season. We had a huge turnaround in the summer and sometimes, when you bring a new group in, it takes time to learn what we want and consistently show that week in, week out.
"But I think in the last two games and 70 minutes versus Southampton, we were really good. It’s just making sure we switch on for 95 minutes of the game.”
After the game, Preston chief Ryan Lowe admitted to being annoyed at the failure to award the visitors a spot-kick after captain Alan Browne went down under pressure from Alfie Jones early in the second half.
It was one of several half-shouts for penalties for each side.
Rosenior added: "I know there’s one, but I cannot think of any others. That one was nowhere near a penalty. Nowhere near.”
The City boss said that loan midfielder Tyler Morton missed the game as a precaution after coming off in the midweek win at Birmingham with a groin issue.
Rosenior said: "He is going to be fresh for West Brom and it is brilliant news. I was really worried when he came off, he had a (later) scan and just felt it wasn’t worth risking him.
"He is a young player who we want to look after and he’s a real gem and talent and he will come right back into my thinking for West Brom.”