Championship leader Max Verstappen's FP2 came to an abrupt end at the Canadian Grand Prix, when his car caught fire just over halfway through the session.
The three-time world champion pulled into the pit lane with his Red Bull smoking as what was suspected to be a brake issue hampered his running, but Sky F1 pundit Ted Kravitz later revealed that it was an issue with the energy recovery system (ERS).
The Dutchman has endured a tricky start to the Canadian GP weekend, as he was two seconds off the pace in a rain-affected FP1, and did not set a representative lap time before his FP2 issue.
Having been wheeled into the garage, Verstappen got out of the car and headed away from the garage, indicating that his Saturday running was over.
Will this affect Verstappen for the rest of the weekend?
The problem means that Verstappen has hardly had any meaningful running across the first two practice sessions, which could impact the rest of his weekend as he looks to return to winning ways.
The Red Bull mechanics immediately got to work, taking tools to the side of the RB20 in an attempt to access the inside of the car to diagnose the extent and cause of the issue.
An ERS issue may not prove to be a simple fix. The system is responsible for harvesting and deploying energy through an electric motor, which can give drivers an extra dose of speed when looking to overtake or simply push harder.
Ted Kravitz revealed that mechanics could be working on the car well into the evening, which may involve the team breaking their curfew to resolve the issue.
"The power unit guys. I think it might be on the energy recovery system," he said on Sky Sports F1. "They are able to diagnose the problem and conclude that something needs changing.
"That’s a job that’s going to take them long into the Canadian night."
There were similarly smoky scenes for Verstappen when he retired from the Australian Grand Prix earlier in the season. That turned out to be an issue with the brakes, but the Red Bull star will be hoping not to see any more smoke over the weekend.