The 18-year-old supplied the cross from which Robert Snodgrass headed home the equaliser after Darren Bent had put Fulham ahead to earn a replay at Craven Cottage a week on Tuesday.
Then he went on to make a piece of quirky footballing history when he was replaced after 79 minutes by his identical twin brother Jacob, who came off the bench to make his senior debut.
Who said there was no longer any magic in the FA Cup?
The Murphys then went home to have their performances analysed by mum Maxine.
"My mum comes to every game," said Josh.
"And then we go home and she will analyse my game. She tells me how I played 'You didn't do this well or you didn't do that well'. She knows her stuff."
The Murphys have come through the Norwich academy and Josh scored a goal in the club's youth cup final victory against Chelsea last season.
His step up to play with the big boys has been seamless judging by the confidence and competence on show on Saturday when his surging wide play tormented Fulham.
"At least we didn't get knocked out of the cup and all the lads are happy," said Josh, who only discovered he was playing at 11am on the morning of the match.
"When I found out that I was in the starting line-up me and my brother just went in the toilets and quickly gave each other a high five.
"It was a big moment for us. I just thought I had to go out there and do my job. I get the ball and get at people. I'm a confident young player who likes to get crosses and shots in."
Even when the substitutes board went up and Jacob came on there was no sense of disappointment.
"There's no rivalry at all," said Josh.
"When I came off I was happy that he was going on because I know what he is capable of.
"It was crazy. I saw him getting undressed and I knew I was going to come off and when I saw him standing there with a little smile on his face it was like, 'It's your turn now'."
Josh, who admits he studies YouTube clips of Cristiano Ronaldo and Lionel Messi to learn his trade, puts his trust in manager Chris Hughton.
"I wouldn't have imagined me playing now," admitted Josh.
"But he (Hughton) knows what he is doing. He's brought me through like he did with Nathan (Redmond) and he's made almost 100 appearances for the senior team.
"I thought I would be playing for the first team but not maybe for another year and a half, so to be playing now is a great feeling."
Meanwhile, all the Fulham talk was about Dimitar Berbatov, who was not in the FA Cup squad.
Berbatov has been linked with a potential January transfer move to Arsenal but Fulham boss Rene Meulensteen was adamant nothing should be read into his absence at Carrow Road.
"No conspiracy there," said Meulensteen.
"It's more looking after a valuable asset of this club. After the recent little injuries he did well against West Ham, so to play again so soon would be not very clever. We looked after him."
Asked whether there was any truth in the Arsenal rumours, however, Meulensteen, who carved his reputation as a first team coach under Sir Alex Ferguson at Old Trafford, had an unfortunate slip of the tongue
"Everybody's assuming (Berbatov will go) but as far as I know he is a Man United player....my mistake. Oh my God. He's a Fulham player."
He swiftly added: "As far as I know he is very content, very happy. He is playing well and is very important for us."