Kimi Raikkonen saw his title hopes dealt a major blow at the Belgian Grand Prix
when he suffered his first retirement since his comeback with Lotus that began at the start of the 2012.
The 2007 world champion had been fighting with Ferrari's Felipe Massa
when he was forced to pull in with brake failure, seeing him slip to fourth in the F1 2013 driver's standings, leaving him over 60 points behind leader Sebastian Vettel.
"I had a brake failure so there was really no point in trying to continue," said Raikkonen. "There were some brake issues at the beginning of the race but we were managing them and it was going okay until we had to retire. We've finished a lot of races and had some good reliability; one day your luck has to run out and today was that day."
The team subsequently said that it believed that a discarded visor tear-off had become lodged in a front brake cooling duct, leading to dramatic overheating in the first stint of the race. Although the obstruction was cleared out during Raikkonen's first pit stop, the brakes never had a chance to cool off and duly cooked themselves to a terminal state.
"Kimi suffered from a brake failure which, of course, is a concern," said team principal Eric Boullier. "We already believe we know why it happened and we will investigate this in detail to prevent the situation arising again.
It was an unfortunate outcome for Raikkonen, who had been making good progress through the field from eighth on the grid despite losing out at the start and dropping back two places on the first lap.
"We both got good starts off the line but there wasn't enough space into the first corner where I went over the kerb and lost some time, but after that I was pushing as hard as I could," he said, managing to climb as high as fifth before his retirement.
Even before Raikkonen's retirement, Boullier had been frustrated by the Lotus race pace on Sunday.
"It was a disappointing weekend," he admitted. "Today we lost some pace and part of that might be due to the low temperatures. We must now look ahead, learn from this weekend and make sure that next year we can deliver on a medium downforce track."
Sharing in the frustration, Raikkonen's team mate Romain Grosjean
could only finish eighth after a one-stop strategy failed to pay off for the Frenchman. At one point he found himself forced across the kerbs at Les Combes when dicing with Sergio Perez, an incident that saw the Mclaren driver penalised and left Grosjean feeling aggrieved.