Juan Pablo Montoya stormed out of Indianapolis Motor Speedway an inconsolable figure on Sunday, leaving in his wake a trail of journalists, despondent Colombian fans and the remnants of his championship dreams.

The Williams man finished sixth in the US Grand Prix, and the result left him unable to catch Ferrari's Michael Schumacher at the top of the drivers' standings with one race remaining.

Barely minutes after the showdown at 'The Brickyard' had ended, and with Germany's Schumacher still celebrating his win on the podium, Montoya hurried out of the Williams hut and away from the famous venue, ignoring the waiting media.

The 28-year-old, who began the day just three points behind his German rival, was left to reflect on a pivotal moment on lap two, when he was given a 'drive-through' penalty after an incident with Ferrari's Rubens Barrichello.

With rain also starting to fall and Montoya struggling to compete on his choice of tyre, it was an early blow from which he never recovered.

Five-times world champion Schumacher took the chequered flag to move on to 92 points, nine ahead of second-placed Kimi Raikkonen with just the Japanese Grand Prix left this season.

Montoya is now stranded on 82 points, and he was so angry he would only issue a statement through his team.

"It is sad to lose my drivers' championship chances in this way," it read, "especially knowing that I just needed to finish fifth today to keep my hopes open.

"It was a disappointing race, basically decided by the penalty I was given for the accident with Rubens.

"In fact, it started to rain hard just when I was given my 'drive-through' penalty, which forced me to delay by one lap my pit-stop to change to wet tyres."

Montoya, who won the Indy 500 here three years ago, was many people's pre-race title tip, and his exploits in Formula One this season have attracted huge interest in his home country.

Thousands of fans, wearing the Colombian colours of red, yellow and blue, were at Indianapolis, eager to urge Montoya towards his goal of becoming the first Colombian to win the world drivers' championship.

Fourth place on the grid was satisfactory, especially with Schumacher behind him in seventh.

But with the pressure on, some may raise questions about Montoya's approach.

Regarded in his early days as unpredictable, Montoya's aggressive nature saw him try to pass Barrichello early on, before coming together with the Brazilian and incurring the penalty that ended prematurely hopes of a dramatic duel with Schumacher.

"We were running side-by-side (into the turn)," explained Barrichello. "I didn't want to turn into the corner, so I went wide... but even so, he touched me.

"It is not for me to say whether his penalty was justified. But I know how crucial it was to the championship."

Mario Theissen, director of BMW motorsport, revealed that Montoya also had to contend with a fuel rig problem and, with team mate Ralf Schumacher not finishing, Williams endured a miserable day.

A deficit of three points now separates them from new leaders Ferrari in the constructors' championship.

"It was obviously a bad day for both championships from our point of view," said Williams chief operations officer Sam Michael.

"We have made quite a lot of mistakes as a team today which we have to address for the race in Japan."