Hosts midfielder Pascal Struijk was sent off for a challenge that appeared to break the 18-year-old’s left leg midway through the second half.
At that point, Liverpool were already ahead comfortably thanks to Mohamed SalahThe 100th Premier League goal and Fabinho’s goal in the 50th minute.
Sadio Mane finished the score in injury time.
However, the loss of Elliott cast a dark cloud over Jurgen Klopp’s positive performance.
Elliott, who made his Premier League debut at age 16 with Fulham, had broken into the Reds’ side with impressive displays early in the season against Burnley and Chelsea.
Liverpool’s title defense was thrown off course last season by a series of long-term injuries to key players like Virgil van Dijk, Joel Matip, Joe Gomez and Jordan Henderson.
Van Dijk’s return from a cruciate knee injury has had a massive impact with Liverpool conceding just once in their first four games.
However, Salah aside, questions remain as to whether Liverpool have the firepower at the other end to match their title rivals Chelsea, United and reigning champions Manchester City.
The visitors should have been out of sight before the break as they calmed the Elland Road crowd, enjoying their second glimpse of a Premier League match in 17 years.
Salah completed a brilliant team play to open the scoring and lift his century in just 162 games in the English top flight, as he and Matip traded a one-two before a Trent Alexander-Arnold center chose the Egyptian for a I touched.
Mane’s form remains a concern for Klopp despite his late goal, as the Senegalese missed a number of golden opportunities, including as he overcame an open goal from a Diogo Jota cross.
After Mane failed to convert a one-on-one with Meslier minutes into the second half, Liverpool finally doubled their lead from the resulting corner.
Fabinho swept home a fumble after Van Dijk failed to connect cleanly with a free header from a corner.
Unfortunately, the main topic of conversation was yet to come as Struijk won the ball in a sliding challenge, but the momentum from the Dutchman’s last leg drove him through Elliott’s back.
The incident took place right in front of the Liverpool bench and Klopp was involved in an angry exchange of words with Leeds fans, who were initially angry that the game was stopped.
Naby Keita, Curtis Jones and Ibrahima Konate were among Liverpool substitutes who covered their eyes in shock from the injury.
However, Elliott was able to applaud Leeds’s support when he was pulled from the field and they gave England’s U-18 international an enthusiastic reception.
Rather than making the man advantage count, Liverpool were slack in the fourth quarter and could have paid when Patrick Bamford’s effort from nearly the half had to be turned over by Alisson Becker.
Mane also missed two more glorious chances before finally scoring his second goal of the season when he jumped on Thiago Alcantara’s pass and crashed into the corner of the car.