Nico Rosberg says Lewis Hamilton can realistically target Michael Schumacher's Formula 1 records of 91 race wins and seven world championships before the end of his current Mercedes contract.
Hamilton sealed his fifth world title in the Mexican Grand Prix, and he currently has 71 wins to his name, and another two years on his deal with Mercedes.
"For Lewis now, with five titles, unbelievable," said 2016 world champion Rosberg, in a message of congratulations he posted on his YouTube channel after the race.
"It's crazy to think, and equalling [Juan Manuel] Fangio [as a five-time world champion] - crazy.
"He can seriously go for Schumacher's records now. He's got two more years on the contract, and Schumi is only two titles away, 20 race wins away, even that's possible in two years.
"It's amazing. He can really try to become statistically the best of all-time, which is unreal, but it is a possibility, and I'm sure he's going to be motivated by that."
Rosberg said it was irrelevant that Hamilton sealed the title with a disappointing fourth place in a race where Mercedes was way off the pace of Red Bull and Ferrari.
Sebastian Vettel finished second, but needed to win with Hamilton eighth or lower to keep the title fight going.
"Today's race was not the best way to finish the season for Mercedes in a race like that, but whatever, it doesn't matter - who cares," Rosberg added.
"The big picture counts.
"You all really deserve it, phenomenal job, especially this year because Ferrari, on average, maybe even had the better car.
"To go with such pressure, to come so strong through the middle part of the season, develop the car so strong, amazing effort.
"After the midway part of the season it really went two ways: Sebastian really struggling, making mistakes, his team making mistakes as well.
"Mercedes and Lewis [were] getting everything perfect, it just completely went apart in a big way.
"That's why it's now such a big difference in the championship, and it's finished so early.
"I hope everybody is going to have a great party tonight!"