The highly-anticipated opening session amid the glittering lights of Las Vegas was called off after mere minutes - when two cars were badly damaged by a manhole cover.

Going into the session, and amid the backdrop of drivers' complaints about the 'show' elements of the race weekend, it was thought the newly-iconic 'Sphere' venue might distract the drivers.

As a result, colours the same as the critical warning flags - red, blue and yellow - were banned from the Sphere for the actual track sessions.

Max Verstappen joked that only seeing his face on the Sphere would be a distraction. "I'd probably smash the car straight into the wall," the world champion laughed.

Mercedes' George Russell agreed that a bigger concern is the layout itself.

"I understand the thinking for overtaking, but I don't think it will be a great track for the drivers," he said.

"But I think it's only long-time fans who appreciate the importance of historic circuits like Silverstone or Monaco. Times are changing and we need to embrace it.

"But will this be good for the racing? I'm sceptical."

Ultimately, though, it wasn't the Sphere or the cold temperatures or the layout that brought opening practice to a halt late on Thursday - but a manhole cover.

"The floor of Carlos Sainz's Ferrari has been badly damaged," reported Speed Week. "The suspension is broken and the survival cell may also be damaged."

Esteban Ocon's Alpine then suffered a similar fate, bringing out the red flags - permanently.

"The FIA reports that it's actually torn out of the asphalt," Auto Motor und Sport declared in its live track commentary.

"Alpine tells us that they need to change the chassis because of the damage."

The German publication continued: "All the other manhole covers now need to be inspected. They then need to discuss with the local engineers how long it will take to find a solution and what impact this will have on the schedule."

Formula 1's governing body then confirmed: "A concrete frame around a manhole cover has failed and all of the other manhole covers need to be checked."

Alpine boss Bruno Famin said it's "possible" the second planned practice session at midnight could be "increased to one and a half hours" to compensate.

"I heard that this is being discussed," he said. "I believe the FIA understands what needs to be done in such a situation, and I have no doubt that they are doing it."

Ferrari boss Frederic Vasseur says Sainz's car is also a write-off.

"This is totally unacceptable," he charged. "The monocoque is badly damaged, as is the engine and the battery. That costs a fortune.

"We certainly won't be able to take part in the second practice session."

Auto Motor und Sport's Tobias Gruner commented: "This is a disaster for Formula 1. No race weekend has ever been accompanied by such hype and the organisers at Liberty Media have invested hundreds of millions of dollars.

"The pressure is high to find a quick solution. Otherwise we are facing a complete farce."

At the time of writing, the situation appears dire - as it emerges that the problem with the offending manhole cover is actually "not an isolated case".

Speed Week's Mathias Brunner reports: "It is unclear whether there can be a second practice session at all."