Formula One champion Michael Schumacher came close to retiring following the terrorist attacks on America.
The revelations were made by Ferrari's technical director Ross Brawn on BBC Radio Five Live, ahead of Sunday's United States Grand Prix.
Schumacher, who is on pole for the Indianapolis race, was deeply affected at the Italian Grand Prix two weeks ago - days after the disaster in America.
"When he arrived in Indianapolis he was still feeling the effects of Monza," said Brawn.
"He did a lot of thinking from then until now. Everybody's affected individually. Michael knows he is a fortunate guy (in Formula One). Its down to his skill. He knows he's a lucky guy.
"He has a lovely family and wonders what would happen if he lost that. He's waiting for the hammer to come down because life is so great.
"He really was badly affected by the disaster. There was talk of retirement. I think a few days of consideration reminded him how much he loves racing."
On Saturday, Schumacher claimed pole position for Sunday's Grand Prix, for the second year in a row.
The world champion posted a time of 1 minute 11.708 seconds on his third flying lap to claim pole with 10 minutes of qualifying remaining.
And when his rivals all went out for one last attempt to dethrone him, Schumacher decided he had done enough and instead opted to watch their progress on TV.
Schumacher, chasing his ninth win of the season, will have Mika Hakkinen alongside him on the front row of the grid, with brother Ralf in third and Juan Pablo Montoya fourth.
Schumacher took nearly half the session to appear for the first time, allowing first Montoya and then Hakkinen to post fastest times.
Fastest time
Schumacher's first attempt saw him only take third as Rubens Barrichello led the way, but with 20 minutes to go the world champion became the first man to go under 1:12.
Hakkinen then posted the fastest time, just two one-thousands quicker than Schumacher, but the world champion stamped his authority on the session with 10 minutes to go.
He recorded 1:11.708 to push Hakkinen into second, and when Tomas Enge went off with five minutes left in the session Schumacher decided to call it a day.
The Williams and McLaren drivers went out for a final fling, but they could not get within half-a-second of Schumacher's time.
Leading positions for US Grand Prix:
1. Michael Schumacher, Germany, Ferrari, 1:11.708
2. Mika Hakkinen, Finland, McLaren-Mercedes, 1:11.945
3. Ralf Schumacher, Germany, Williams-BMW, 1:11.986
4. Juan Pablo Montoya, Colombia, Williams-BMW, 1:12.252
5. Rubens Barrichello, Brazil, Ferrari, 1:12.327
6. Nick Heidfeld, Germany, Sauber-Petronas, 1:12.434
7. David Coulthard, Great Britain, McLaren-Mercedes, 1:12.500
8. Jarno Trulli, Italy, Jordan-Honda, 1:12.605
9. Jean Alesi, France, Jordan-Honda, 1:12.607
10. Jenson Button, Great Britain, Benetton-Renault, 1:12.805