The £5.1 million recruit, who was the first player Jurgen Klopp signed as Reds boss, was the standout star in the 5-0 victory against the Cod Army
The Serbian starlet, recruited from Red Star Belgrade for £5.1 million, had to wait a long time before he could line up for Jurgen Klopp.
He was signed in January, but remained at his boyhood club on loan until the end of the season to help them clinch the SuperLiga title. They did so by a mammoth 28 points.
The midfielder reported to Melwood for the start of pre-season on July 2, but then had to be patient as work permit proceedings were undertaken.
He attended a hearing in Manchester two days later, which Klopp presented testimony in, and was successful in his application.
But another barrier remained before the Under-20 World Cup winner could represent the club.
Grujic had to leave the country and re-enter in order for his work permit to take effect, which meant he missed Liverpool’s 1-0 win at Tranmere as they kicked off their preparations for 2016-17.
On Wednesday night, as the wind blew wildly at Highbury and he made an impact as large as his 1.9 metre frame, the wait was worth it.
Grujic’s physicality, turn of pace and trickery earned Liverpool a penalty on 12 minutes, with Danny Ings’ spot-kick saved.
Six minutes later, a lovely ball from Joel Matip was played into Sadio Mane, who combined with Alberto Moreno. The ball broke for the 20-year-old and he took a touch before a slight deflection helped his strike beyond goalkeeper Chris Neal.
Grujic was not done either. Just four minutes after opening the scoring, he rattled the post from a tight angle and then continued to be the standout player of the first half.
He displayed a sample of the qualities that prompted Liverpool to offer him a five-year deal; strength, composure, dynamism, skill and tactical intelligence.
Klopp admitted Wednesday night’s encounter was the first time he watched Grujic perform live in a game.
He applauded from the dugout and wore a gigantic smile as the starlet converted, and then let out an ‘oooofh’ when he struck the woodwork.
The manager was impressed, and he wasn’t alone.
"He scored a goal in his first game in the first situation – it’s a dream," said Klopp.
"You saw it, in a friendly game not often a player celebrates like him but obviously it was a big moment.
"It was nice to see."
It was only a pre-season friendly. It was only a 45-minute run out. And it was only against Fleetwood.
But Grujic was hopefully starting as he means to go on.