Rosberg needs to win in Brazil on Sunday to have a real shot at his first title. Hamilton just needs to stay close to his teammate to close in on his second driver's title.
The championship can't be decided at Interlagos this weekend because the race in Abu Dhabi will be worth double points, but the result in Sao Paulo will determine how the title fight will be set up for the finale.
Hamilton has a 24-point lead and would clinch the title with consecutive second-place finishes or by coming third in Brazil and a second in Abu Dhabi. Rosberg will need to be nearly perfect in both races to keep his hopes alive.
"It's clear that I need to rely on something happening," Rosberg said. "For sure it's not enough for me to win, unfortunately, but that's the way it is. In sports, so much can happen, so I'm still very optimistic."
Hamilton has been on a remarkable run in the final part of the season, winning five straight races to open up a big lead going into the decisive races. He started behind Rosberg in two of the last three races but was still able to overcome his teammate and finish with the victory.
"It's been quite a phenomenal season," Hamilton said. "This year, for sure, has been the best year of my career. I feel like I've grown as a driver."
The 29-year-old Rosberg led the drivers' standings early in the season but failed to keep up with Hamilton in the later part. He hasn't won since the German GP at home in July, eight races ago. He stayed within range of his teammate by finishing second in five of the last six races.
The start of Rosberg's struggles began almost at the same time as his relationship with Hamilton deteriorated following contact between them at the Belgian GP. The 29-year-old British driver was angry about being taken out by his teammate and Rosberg was also criticized by team officials.
"I don't think anything has changed," Rosberg said. "It was an intense battle before and it still is an intense battle now. I don't know his exact opinion on things, but for me nothing has changed since then.
"Lewis has done a little bit of a better job since then. That's it, pretty simple," Rosberg added. "But as I say, still two races (left)."
The title race remains undecided in great part because of the rule change that made the season-ending race worth double points, a move aimed at keeping fan interest alive throughout the season.
"Great news that for sure this year I have a chance to win the championship the way it is now, that's a good thing," Rosberg said. "I'm also happy because it's good for the fans and that it's going to be exciting until the very end. For sure it keeps me very, very optimistic."
It will be the last race at Interlagos before an extensive renovation at the paddock and pit areas. There were some safety changes for this year, including the addition of runoff areas and a new pit entrance and pit exit.
"It's a lot safer now," Williams driver Felipe Massa said. "I hope we will see less accidents than in the past."
Rain is expected for the weekend, which could add even more unknowns to the title race. The Abu Dhabi GP will be on Nov. 23.
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