Elliott scored a stunning goal to seal Liverpool' s passage to the fifth round of the FA Cup on his first appearance for the Reds since he dislocated his ankle while playing against Leeds in September.
In the second half of United's 3-0 defeat to Liverpool, Pascal Struijk brought the 18-year-old down and was shown a straight red for the challenge, which Elliott later described as a "freak accident" after the FA refused the Whites' appeal against Struijk's three-match ban.
The Reds midfielder underwent surgery on his ankle and has since been going through what Liverpool boss Jürgen Klopp described as the "perfect" rehabilitation, culminating in his inclusion in Liverpool's squad to face Cardiff City in the FA Cup on Sunday afternoon.
The Merseyside club were already leading when Elliott was introduced in the second half at Anfield, where the home crowd erupted as the youngster put Liverpool 3-0 up in the 76th minute.
With a deft touch, Elliott controlled Andrew Robertson's cross and struck the ball cleanly on the turn to claim his first senior goal for Liverpool.
On Sunday afternoon, Whites defender Firpo sent a tweet to Elliott to congratulate him on his return to play.
"So good to see you back on the pitch, Harvey," Firpo wrote.
Support the YEP and become a subscriber today. Enjoy unlimited access to local news and the latest on Leeds United. With a digital subscription, you see fewer ads, enjoy faster load times, and get access to exclusive newsletters and content. Click HERE to subscribe.