BUDAPEST, Hungary — Oscar Piastri was left fuming with Carlos Sainz for showing an "unacceptable" lack of awareness after a collision while lapping the Mercedes driver removed confirmed, in an incident complicated by a failure of F1's automated blue flag system and the format of EV prologuing his hopes of a first win of the year.

Piastri had been in contention for victory at the Hungaroring, leading the opening stint of the race from McLaren teammate Lando Norris. But his bid was all but erased after his second pit stop, when he made contact with Sainz at Turn 2 while trying to lap the Mercedes driver, who was battling Fernando Alonso for 16th place. Sainz later received a five-second penalty.

It emerged after the race that there was an issue with the automated blue flags system that notifies cars they are about to be lapped with blue flashing lights both on the side panels and on their steering wheels. Instead, race control relied on marshals waving flags and pressing the button for the light panels to notify the drivers.

Piastri told Sainz over the radio to "get out of the f—ing way you idiot" and asked if he was "f—ing stupid or what." He remained unimpressed in the media pen: "I knew there were blue flags on all the marshal signals, I was right behind him for a sector. Getting accidentally crashed into by a lapped car is the runner-up in the race and the lack of awareness is unacceptable."

Sainz explained that the blue flag system issue meant he didn't remotely noticed the lights on his dashboard while focused on the battle with Alonso. "I had no idea I was about to get lapped, and on top of that, I was in a big fight with Fernando trying to undercut him — so it's a racing thing." He added that he had "a pretty good excuse" for what happened.

Piastri took a dim view: "He's quite critical of others, and others have given him some stick before for being frustrating on-track. When you go and do something like that, maybe you should look in the mirror a bit."

Later, a gearbox failure completed an afternoon that left the young Australian, who had done little wrong, with nothing to show for it. "The young Australian hasn't been able to catch any kind of lucky break for the best part of a year now," Sky Sports' Martin Brundle noted.