Pirelli clams that its initial investigation into Max Verstappen and Lance Stroll's Baku punctures were caused by debris.

Indeed, the Italian manufacturer has revealed that it has also discovered a cut on the left-rear tyre on Lewis Hamilton's car.

Following the numerous red flags witnessed during qualifying, it was widely expected that more would follow on race day. However, a clean opening lap suggested that those fears were not to be realised.

Then, on lap 29, Lance Stroll suffered what appeared to be a high-speed blow-out on the main straight which sent his car into the wall with devastating effect.

Numerous replays of the incident revealed the Canadian's left-rear tyre to have punctured.

The race was subsequently restarted, only for race leader, Max Verstappen to suffer the same fate on lap 45, his left-rear suddenly failing, sending him into the wall also.

Aware that both left-rears had failed, Red Bull's sporting director, Jonathan Wheatley radioed race director, Michael Masi to red flag the race and allow all drivers to change tyres for reasons of safety. The race was indeed subsequently red flagged.

Ahead of the restart, Christian Horner could be heard explaining to Helmut Marko that tyre failure was suspected, the Briton pointing to the fact that in both instances it was the left-rear.

Initial investigations by Pirelli however suggests that it was debris, as opposed to tyre wear that caused the two high-profile crashes, the Italian manufacturer revealing that cuts were also found on Lewis Hamilton's left-rear tyre.

"I believe I can exclude that failures were due to tyre wear, because it is not a matter of tyre wear," said Pirelli's motorsport director, Mario Isola.

"We found a cut on the inside shoulder of the rear left tyre used by Hamilton in the same stint," he added. "The cut was quite deep and big, probably 6-7 cm, but not cutting the construction, so the tyre was still in one piece.

"Just the tread is cut," he continued, "and when there was the red flag and Lewis came to the pit lane and changed tyres we were able to find the cut.

"The left rear is not the most stressed in Baku," he insisted, "as talking about the tyres it is obviously rear right. This is the preliminary investigation."

Isola went on to claim that the very nature of the failures points to debris as opposed to wear.

"There was no sign, or any warning, according to the teams," he said. "We have yet to receive the telemetry from them, but they told me there was no warning, no vibration, nothing to think there could be something in the tyres.

"Consider that the tyres fitted on the cars that crashed were back in the garage and in our fitting area just minutes ago, we need a bit of time to analyse them, I don't want to give any preliminary conclusion.

"But it seems it is a cut due to debris," he added. "It is not a more-stressed tyre and we have evidence of another cut in the same position. Both the accidents happened on more or less the same part of the circuit and a few laps difference, so we have other cars with the same number of laps, same tyres, without any issues.

"So the preliminary investigation is that it is probably due to an external factor or debris, kerb, or whatever, but I don't want to jump to a conclusion now as the plan is to make a thorough investigation and make a report to the teams and the FIA that will be hopefully before Paul Ricard. Obviously it is a priority."

Check out our Sunday gallery from Baku, here.