The German made contact with the rear of the BAR driven by Sato on lap seven of the Japanese Grand Prix and was forced to make a pit-stop for repairs to a mangled front wing on his Ferrari.
"In Formula One, you accept that if somebody leaves the door open like he did you are allowed to go through," said Schumacher, who clinched the championship after team mate Rubens Barrichello won the season-ending race at Suzuka.
"But obviously (Sato) saw it differently and decided at the last moment to slam the door shut on me. It was hard to avoid him and I lost my nose."
The incident sent Schumacher to the back of the field and gave a glimmer of hope to rival Kimi Raikkonen, who needed to win the race and hope the German failed to score to snatch the title.
The Finn instead had to settle for second.
Sato, racing in his first Grand Prix this year after replacing Jacques Villeneuve at BAR, had his own assessment of the run-in, which happened on entry to the chicane.
"It was not the right distance for Michael to overtake me perfectly, so I just took my usual line," said Sato.
OPTIMISTIC
"He was probably a bit optimistic about coming around me and unfortunately we made contact.
"At the end of the day I just want to congratulate him on his sixth world championship. That was really superb, mega."
The Sato incident was not the only scare for Schumacher, who was almost shunted out by younger brother Ralf later in the race.
But he battled back through traffic to finish eighth and secure the point that made Raikkonen's position academic.
"It was a crazy day and one of the toughest races I have ever had," said Schumacher. "I was a little bit messy today after having that little incident and then ... with Ralf hitting me.
"I locked up so tight when Ralf hit me that I was almost losing vision on the straights the vibrations were so huge."
A relieved Schumacher said that the achievement of overtaking Argentine Juan Manuel Fangio, who won five titles in the 1950s, would take time to sink in.
"I have mixed feelings," said the 34-year-old. "Most of my championships have come with a victory but I really had to make sure to be in eighth position."
"You have to think about the worst to be safe."
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