Lewis Hamilton called himself an idiot after his worst qualifying drive this season left him starting 12th for the Italian Grand Prix on Sunday.
Hamilton, who won at Monza last year, was chasing a fifth successive pole position in Formula One but he failed to even make Q3 on Saturday.
"I just drove like an idiot," he said. "That's the worst I've driven for a long, long time. I'm sorry to the team."
Hamilton was third after Q1 but then drove into the dirt before getting caught behind Force India's Adrian Sutil on his final lap. Sutil was later demoted three places on the grid - from 14th to 17th - although a stewards' inquiry determined he hadn't intentionally impeded Hamilton.
"Yep (I was impeded), but there's nothing you can do about it," Hamilton said.
"I should have done a lap before that. I just didn't drive well. I was quick in Q1 and then I don't know. I'll do whatever I can from where I am but it's going to be tough."
It is Hamilton's lowest position on the grid since last year's Spanish GP, where he was demoted to last place after a mistake from McLaren put him in breach of F1 rules.
"Someone said it's been 67 races since I've not qualified for Q3 so I guess I can be a little bit easy on myself," Hamilton said. "But I just want to achieve the best for the team, they're working so hard. Sometimes you just have those moments but tomorrow I've got to get the points and I will do everything I can to get those."
Hamilton trails championship leader Sebastian Vettel in third by 58 points in the standings. Vettel will start in pole position on Sunday.
Hamilton can take inspiration from Sergio Perez's fantastic drive at Monza last year where he powered through the field to finish second despite starting in 12th.
It was also a disappointing qualifying session for Kimi Raikkonen, who will start 11th. Both Lotus drivers failed to make Q3 and teammate Romain Grosjean will be 13th on the grid.