White smoke and sparks burst out from below the car when it made contact with the cover on the new street circuit along the famed Las Vegas Strip.
Ferrari's survival cell, engine, battery and control electronics were all damaged beyond repair during the incident, which Ferrari team principal Frederic Vasseur called "unacceptable."
"I think it's tough for a team to arrive in Vegas and to have this kind of incident," he said.
The car left the track on the back of a truck but returned with Sainz behind the wheel when action resumed more than five-and-a-half hours later at 2:30 a.m. local time following repairs to the 3.8-mile course.
Despite damage to the car due to what the governing FIA called "highly unusual external circumstances," the stewards said Sainz would still suffer a 10 place grid penalty for Saturday's race.
Alpine said Esteban Ocon's chassis would also need to be replaced due to suspected damage from the cover, and FIA said it would check all of the covers along the 3.8-mile street circuit on the famed Las Vegas Strip.
Team principals were quick to defend the brand new course and the massive investment that has gone into staging the event for the first time in the heart of bustling Las Vegas, a move that has drawn criticism from local residents.
"I'm still convinced that the event is mega for the F1," Vasseur said, noting that issues with manhole covers had impacted races in Monaco and Baku in the past.
"This is probably going to be one of the most watched Grand Prix in the history of the sport," said McLaren CEO Zak Brown.
"We have a tremendous amount of corporate partners out here, lots of fans, lots of attention on this sport as a whole and I think it's (F1 owner) Liberty taking the sport to yet another level."
Mercedes team principal Toto Wolff lashed out at a reporter who asked how the cancelled practice was not a "black eye" for F1. "That's completely ridiculous," Wolff said.
"How can you even dare to talk bad about an event that sets the new standard, and you're speaking about a ... drain cover that's been undone. It's happened before, it's nothing."
Leclerc led the time sheet with a lap of 1:40.909, followed by the Haas duo of Nico Hulkenberg and Kevin Magnussen.
The practice sessions along the transformed Strip mark F1's return to Las Vegas for the first time in nearly 40 years but they proved anti-climactic to the fans who packed into the stands on Thursday and were cleared out before the second session began.
Fans packed into the stands to see the highly anticipated track in action during its debut were disappointed as was American Logan Sargeant, the only driver who did not make it out on the track.
"Well... that was fun," the Williams driver posted on X.
A second practice session is scheduled to take place later in the night on Thursday and conclude early Friday morning.w standards for everything, and you're speaking about a ... drain cover that's been undone. It's happened before, it's nothing."
