Fulham recorded their first point of the season at Bramall Lane on Sunday but their talisman Mitrovic missed a penalty and then conceded one at the other end for Chris Wilder’s side’s late equaliser.
“He’s fine, he was bitterly disappointed,” Parker said when asked about the Serbian.
“He was very quiet after the game, what you’d expect from any player. He had a bad game, the last game in his eyes, and this can happen.
“I said that after the game, this is what happens in football and it can happen to any player.
“At times you can have one of those days and Aleksandar will be the first to put his hand up and say it wasn’t his day and it didn’t go well for him.
“I said after that what would be the making of him is how you react to those adverse times or those bad times as such are the real character of people and what determine them.”
Mitrovic was the Championship golden boot winner last season with 26 goals, and earlier this term headed home his 50th goal for the Cottagers, and Parker expects the striker to recover.
He added: “Of course he was quiet after the game and the next day even but since then he’s someone who has been truly focused on the weekend and obviously putting in a better performance – although I don’t want to say that because his overall performance was good.
“So it wasn’t about the actual performance it was about what he’s going to judge himself on, and centre-forwards judge themselves on goals.
“And of course missing a penalty and a couple of chances which on another day he would put in and of course he didn’t, but I know what he’s made of and I know what he’s about and he’ll be fine.”
Fulham will take on Crystal Palace on Saturday at Craven Cottage as they bid to improve their points total and continue moving forward following four successive defeats in the first four matches of the season.
On Saturday’s match, Parker said: “I feel like we have improved and we’ve been very, very close and of course come the weekend against Crystal Palace now it’s a game that we’re looking at to try and get points out of.
“OK, they’ve done very well and they’re a very experienced team that are very well-coached and with a very good manager.
“We understand the difficulties that brings and in saying that I see my team in the right frame and pushing and hopefully we can do that, we can apply ourselves like we have over the last few games and we can put ourselves amongst it a little bit and try and get a result.”