Schumacher hits top gear again
The five-time world champion finished over 0.5 seconds ahead of closest challenger Eddie Irvine, who followed up his unexpected podium place in Italy a fortnight ago.
Barrichello was unhurt despite slamming into a concrete wall midway through the first session after losing control on the final turn.
The Brazilian was powerless as his car shot across the track before hitting the wall leaving debris strewn everywhere.
The left-rear tyre was also ripped off before the damaged car came to a stop in the home straight forcing race officials to halt the hour-long session.
Barrichello was on his first flying lap and was forced to sit out the rest of the day because his car could not be repaired in time, ending up bottom of the time-sheets.
The Sao Paulo-born driver needs three points from Sunday's penultimate race of the season to be certain of finishing runner-up in the championship to Schumacher.
Barrichello will be confident of shooting back up the standings when practice resumes tomorrow after watching from the pit-wall as Schumacher proved the Ferrari is well ahead of the pack.
Schumacher had missed the remainder of the first session while the team tried to discover what caused Barrichello's accident with mechanics also inspecting where he hit the wall.
But his place at the head of the field was never threatened on a track where he won in 2000 when Formula One returned to the United States and finished second last year.
Irvine proved his recent points finishes in Belgium and Italy were no fluke with second fastest time of the session on a day that Ford reaffirmed its long-term commitment to Jaguar Racing.
The 36-year-old Ulsterman whose future has still not been confirmed though it is becoming increasingly likely he won't stay with Jaguar was the only driver to get within a second of his former Ferrari team-mate.
But Irvine's session almost ended in a collision with fellow Jaguar driver Pedro de la Rosa with the Irishman forced to swerve off line.
David Coulthard posted the third-quickest time but was almost 1.4 seconds adrift with McLaren-Mercedes team-mate Kimi Raikkonen fourth-fastest.
Times after first practice: 1 Michael Schumacher (Ger) Ferrari One Minute 13.548 Seconds, 2 Eddie Irvine (Gbr) Jaguar at 0.575 secs, 3 David Coulthard (Gbr) McLaren at 1.371, 4 Kimi Raikkonen (Fin) McLaren at 1.438, 5 Jacques Villeneuve (Can) British American Racing at 1.487, 6 Heinz-Harald Frentzen (Ger) Sauber at 1.588, 7 Giancarlo Fisichella (Ita) Jordan at 1.661, 8 Jarno Trulli (Ita) Renault at 1.708, 9 Nick Heidfeld (Ger) Sauber at 1.712, 10 Ralf Schumacher (Ger) Williams at 1.743, 11 Pedro de la Rosa (Spa) Jaguar at 1.756, 12 Mika Salo (Fin) Toyota at 1.873, 13 Jenson Button (Gbr) Renault at 2.000, 14 Allan McNish (Gbr) Toyota at 2.041, 15 Mark Webber (Aus) Minardi at 2.081, 16 Juan Pablo Montoya (Col) Williams at 2.084, 17 Takuma Sato (Jpn) Jordan at 2.111, 18 Olivier Panis (Fra) British American Racing at 2.393, 19 Alex Yoong (Mal) Minardi at 2.590, 20 Rubens Barrichello (Bra) Ferrari No Time.
