Following Romain Grosjean's first session crash, Mark Webber on Friday became the second victim of the walls that run alongside the Singapore layout.
The Australian driver, who earlier played down his chances of winning the world championship despite maintaining an outside mathematical chance, hit the wall hard on the inside of the final corner under the lights of the second practice session at Marina Bay.
The 90 minute session, topped by his Red Bull teammate Sebastian Vettel, was red flagged to clear the debris and his damaged Renault powered car.
Webber, 32, had said 24 hours ago that Jenson Button's substantial points advantage over the two Red Bull drivers was too great to bridge with four races to go.
"The championship is very difficult now. I think Jenson has to get four or five points on us and it's all over," he said.
