The Colombian believes last weekend's race wrecked any title hopes left for those chasing Johnson, as the reigning champion was the only one able to stay out of trouble in the incident-filled closing laps.
"Realistically speaking, I think he's got it in the bag, unless something really bad happens to him on Sunday," said Montoya. "We still have three races left and there can be incidents and other things, but you look at last weekend and it was a bad race for everyone trying to chase him.
"Out of the top five in the championship, Jimmie was the only one who didn't wreck, so it was costly for the rest of us points wise."
Montoya believes his points deficit entering the Chase this year was already a handicap for him in terms of his championship hopes. He says he needs to win more races next season in order to be in a better position to contend for the title.
"I think next year we need to be in the top five in the points before the Chase starts," said Montoya. "This year we were in, but we never thought we were going to be really fighting for the championship.
"Next year in order to be more in contention from the beginning, we need to win races before the Chase, because this year we didn't have any bonuses to start with and we were already behind.
"But I still keep an open mind for the next three weeks. Hopefully we can win one before the season is over."
Montoya is currently fourth in the standings and is only 55 points behind Mark Martin, who trails Johnson by 184 points entering the eighth race of the Chase this weekend.
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