Media reports suggested the McLaren driver, whose wife is Japanese, was likely to announce at this weekend's Japanese Grand Prix that he would be leaving Formula One at the end of the year.
The German becomes the fourth quadruple champion and only the third driver to land four titles in a row after Germany's seven-times winner Michael Schumacher and the late Argentine Juan Manuel Fangio.
Ferrari felt the pain on Sunday after emerging with just two points from a hard day in front of their home fans at the Italian Grand Prix.
Paul di Resta suffered his third retirement in a row and Adrian Sutil sneaked into the top-10 in the last lap as Sahara Force India added one point to their tally from the exciting Singapore Grand Prix, where fortunes swung like a pendulum for the Indian F1 team.
Formula One needs to change its new qualifying format after it fell flat at Saturday's Australian season-opener and tweaks can be made before the next race in Bahrain, according to the sport's commercial supremo Bernie Ecclestone.
Summary of sports events and persons who made news on Saturday
The Briton, who started his career working for the Hesketh team in 1977, died in Melbourne of a pulmonary embolism, it said.
Meet Lando Norris, who pipped Lewis Hamilton in the Austrian F1 on July 5 for a podium finish.
Formula One championship leader Nico Rosberg put Mercedes on pole position for the Bahrain Grand Prix on Saturday and ended team mate Lewis Hamilton's hopes of a hat-trick.
Triple Formula One world champion Lewis Hamilton won the Hungarian Grand Prix on Sunday to seize the championship lead from team mate Nico Rosberg for the first time this season.
A summary of sports events and sports persons, who made news on Friday
Ferrari had every hope of winning their home Italian Grand Prix for the first time since 2010 on Sunday and they blew it.
Lauda won two world championships in 1975 and 1977 with Ferrari and a third in 1984 with McLaren. His rivalry with British driver James Hunt, the 1976 champion for McLaren, was intense and became the subject of the acclaimed 2013 film "Rush".
Ferrari's Kimi Raikkonen took pole position for the showcase Monaco Formula One Grand Prix on Saturday with world championship leading German team mate Sebastian Vettel alongside him on the front row.
Quadruple Formula One world champion Sebastian Vettel went for five on Friday with the German choosing to have that numeral on his car when he is eventually deposed as number one.
The 2019 Formula One world championship starts on March 17 with 21 races in a season that ends later than any since 1963.
The clock is ticking for some of Formula One's big name drivers, with world champions and race winners out of contract at the end of the season and a restless young generation eager to take their places.
Ferrari are giving Sebastian Vettel the Michael Schumacher treatment, according to the German's main title rival Lewis Hamilton.
Formula One has lost another of its principals.
Formula One rookie George Russell's earliest motorsport memory is of pedalling a toy tractor around Britain's go-kart paddocks.
Formula One's 'silly season' of rumour and speculation is heating up.
Regarded as the Oscar of sports, the nominations for 2018 Laureus World Sports Awards were finalised following a ballot by the world's sports media.
Summary of sports events and persons who made news on Monday
Next year's season-opening Australian Formula One Grand Prix in Melbourne has been brought forward to March 20, to allow space for an August break, after previously being listed for a later than usual start on April 3.