Disaster has struck for Scott McLaughlin after the Supercars series leader crashed in qualifying for Gold Coast 600’s final race on Sunday.

The 20-minute session ended under a red flag after McLaughlin’s Mustang hit the inside kerb at 140km/h at the tough concrete wall lined street circuit and ended up on its side on turn four.

Remarkably, Shane van Gisbergen, McLaughlin’s main rival for the Supercars title, stopped his Holden and raced over to help the Ford star out of his badly damaged vehicle.

McLaughlin was fastest in the session for Sunday’s 102-lap race but it remains to be seen if his Ford outfit can repair his car in time for the top 10 shootout starting at 1250 AEDT.

McLaughlin walked away from the wreck but is being monitored at the track’s medical centre.

He had hoped to wrap up back-to-back championships on Sunday but there is a huge question mark over whether he will contest the final 300km race of the weekend.

McLaughlin’s withdrawal on Sunday would throw the championship door open for van Gisbergen.

The Kiwi whittled away at the series deficit when he finished second behind Jamie Whincup with McLaughlin third in Saturday’s opening 300km event.

Van Gisbergen cut McLaughlin’s series lead from 622 to 613 points.

McLaughlin could have wrapped up the 2019 title if he ended this weekend on the Gold Coast with a 600 point lead over van Gisbergen with two rounds remaining.

Van Gisbergen eventually topped the timesheets for qualifying with a lap of 1 min 10.32sec after McLaughlin was dropped to second spot, losing his fastest time for triggering the red flag.

Meanwhile, there was drama before Sunday’s qualifying with Holden’s Richie Stanaway stood down by Garry Rogers Motorsport due to disciplinary reasons.

Stanaway was replaced by Dylan O’Keeffe, who will partner Chris Pither for Sunday’s race.

O’Keefe’s injection was so last minute that he had to borrow Pither’s race suit and helmet for the morning qualifying session.