Hamilton goes out on lap one in Monza (UK only)
By Sarah Holt
BBC Sport at Monza
McLaren star Lewis Hamilton blamed himself for putting his title bid in jeopardy after crashing out of the Italian Grand Prix on the first lap.
Hamilton retired at Monza after damaging his car when he tried to pass Felipe Massa's Ferrari, and as a result dropped to second in the championship.
"It's not over," Hamilton told BBC Sport. "But it is mistakes like I made today that lose world championships.
"I only have myself to blame and I am very disappointed in myself."
A good start saw Hamilton gain a place from his grid position of fifth, but his eagerness to push further up the order cost him.
Hamilton admits to 'mistake' on first lap
His McLaren suffered front-suspension damage as he tried to squeeze past Massa at the second chicane.
"I had a good start and in the realistic world I should perhaps have stayed there for a while," said Hamilton, the 2008 world champion.
"I was just trying to position the car in a certain way, got too close to Felipe, he clipped my wheel and damaged the front of the car.
"There was nothing I could do. It's a little bit of a shame and I apologise to my team."
With five races left in a hotly-contested drivers' contest, another retirement is costly to Hamilton's quest for a second title.
Red Bull's Mark Webber regained his championship lead after finishing sixth and is now five points ahead of Hamilton and 21 in front of Ferrari's Fernando Alonso, the winner of Sunday's Italian Grand Prix.
Hamilton added: "My eyes aren't on Mark [Webber].
"I really have to collect my thoughts and move on to the next race [in Singapore] to try and help the team collect as many points so either myself or Jenson [Button] can win the championship."
You've got to make the best of your opportunities, so it wasn't the best day. We underperformed as a team and just sniffed around getting a few points.
McLaren team principal Martin Whitmarsh was philosophical about Hamilton's retirement and predicts there will be many more twists as Formula 1 heads off on five long-haul races.
"It was a racing incident," Whitmarsh told BBC Sport. "Lewis was pushing very, very hard and you have to do that.
"It was disappointing but you have to rebuild from this.
"It is business as normal. The championship is still tight and could go any way. It is epic; the best championship in history."
Webber took advantage of Hamilton's error to move back into the championship lead, but the Red Bull driver was frustrated to finish in sixth place.
Webber frustrated with Red Bull 'underperformance'
"You've got to make the best of your opportunities, so it wasn't the best day," said the Australian.
"We underperformed as a team and just sniffed around getting a few points."
Hamilton's team-mate Button hauled himself back into contention for back-to-back world titles with second place in Monza.
The defending champion is 22 points behind Webber with five races left, with only 24 points covering the top five drivers in the championship.
Button charged ahead of Alonso at the start but lost out in the pit-stops as Alonso, who stopped one lap later, returned to the track ahead of the McLaren driver.
"Jenson drove a fantastic race," Whitmarsh added. "He had the bottom of his rear-wing end plate munched off by Alonso [on lap one] but that wouldn't have helped the cause anyway, so we're not looking for excuses."
Button explained: "I pitted before Alonso but, when I went out on harder tyres, I couldn't find any grip.
"It's a difficult call but, without knowing all the details, I think it was the wrong call.
Button frustrated by lack of pace (UK only)
"I've lost points from what I thought I was going to achieve. But it's still a very good result and I'm still only 22 points behind."
Vettel, who finished fourth in Italy, was relieved to stay in the championship hunt.
The German lost ground at the start, then ran wide at the first corner when he was hit from behind. Later, he lost more places when a glitch on his Red Bull slowed him momentarily.
Vettel said: "It didn't look too good, but I had to wait and see what chances I might get and then use them.
"It all worked so we can be proud of ourselves. I went flat-out and just tried to come back."
Red Bull team principal Christian Horner said: "This was always about damage limitation. It's a great performance for us today - to take the lead in the drivers' championship [with Webber] and extend it in the constructors'.
"Every proper team will be bringing a big update to the next race in Singapore. There's a few tracks that should play to our strengths, a few a bit more neutral, but nothing like here."